Camelot: a Computer Automated Micro Extensometer with Low-cost Optical Tracking

Camelot: a Computer Automated Micro Extensometer with Low-cost Optical Tracking | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Method Article Camelot: a Computer Automated Micro Extensometer with Low-cost Optical Tracking Nicola Trozzi, Wiktoria Wodniok, Robert Kelly-Bellow, Andrea Meraviglia, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5828617/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Background: Plant growth and morphogenesis is a mechanical process controlled by genetic and molecular networks. Measuring mechanical properties at various scales is necessary to understand how these processes interact. However, obtaining a device to perform the measurements on plant samples of choice poses technical challenges and is often limited by high cost and availability of specialized components, the adequacy of which needs to be verified. Developing software to control and integrate the different pieces of equipment can be a complex task. Results: To overcome these challenges, we have developed a computer automated micro-extensometer combined with low-cost optical tracking (Camelot) that facilitates measurements of elasticity, creep, and yield stress. It consists of three primary components: a force sensor with a sample attachment point, an actuator with a second attachment point, and a camera. To monitor force, we use a parallel beam sensor, commonly used in digital weighing scales. To stretch the sample, we use a stepper motor with a screw mechanism moving a stage along linear rail. To monitor sample deformation, a compact digital microscope or a microscope camera are used. The system is controlled by MorphoRobotX, an integrated open-source software environment for mechanical experimentation. We first tested the basic Camelot setup, equipped with a digital microscope to track landmarks on the sample surface. We demonstrate that the system has sufficient precision to measure the stiffness in delicate plant samples, the etiolated hypocotyls of Arabidopsis , and were able to measure stiffness differences between wild type and a xyloglucan-deficient mutant. Next, we placed Camelot on an inverted microscope and used C-mount microscope camera to track displacement of cell junctions. We stretched onion epidermal peels in longitudinal and transverse directions and obtained results similar to those previously published. Finally, we used the setup coupled with an upright confocal microscope and measured anisotropic deformation of individual epidermal cells during stretching of an Arabidopsis leaf. Conclusions: The portability and suitability of Camelot for high-resolution optical tracking under a microscope make it an ideal tool for researchers in resource-limited settings or those pursuing exploratory biomechanics work. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Background In plants, growth and morphogenesis depend on the interaction of genetic networks, cell signaling, and mechanical forces. Turgor pressure within cells stretches the cell wall elastically, and under the influence of wall modifiers such as expansins, this tension causes the wall to expand through creep (1, 2). Creep occurs in the presence of cell wall modifiers when tensile stress exceeds a specific yield threshold, as described in Lockhart's growth framework (3-5). According to this framework, growth depends on the product of extensibility factors and turgor pressure exceeding the yield point. While expansins promote creep without affecting wall elasticity (4, 6), other proteins like xyloglucan endotransglucosylase/hydrolases (XTHs) also contribute to wall extensibility (7). On the other hand, wall stiffening can limit growth, as seen in cytokinin-induced cessation of root elongation (8). In recent years, novel methods have been developed to measure mechanical forces in plant tissues with most observations relying on stretching tissues with an extensometer and applying localized compression to cells or specific regions using an indenter (9-11). Extensometers quantify the stiffness of materials and how they respond to mechanical forces, allowing to evaluate elastic and plastic behavior, stress tolerance and fracture, and structural behavior. To measure the mechanical behavior of plant tissues, extensometers record how samples respond to applied forces. These devices quantify properties such as elasticity, creep, and yield stress of soft tissues by stretching samples while monitoring force and displacement. Strain is calculated by dividing displacement by the initial length, and stress is calculated by dividing force by the cross-sectional area. The stress-strain relationship over short time scales indicates stiffness, while creep is determined by measuring strain under constant stress over longer periods. Yield stress represents the minimum force required to initiate creep. Factors such as water movement in living tissues or cell wall viscosity in isolated samples can affect these measurements, causing relaxation or reversible deformation. Precise control of force, displacement, and timing is essential for accurate quantification of these mechanical properties. Early extensometers often used weights to measure creep (12). While simple and low-cost, these systems lack precise control over sample deformation, making them less suitable for stiffness tests on very small samples like Arabidopsis hypocotyls. Modern micro-extensometers, designed for such samples, typically employ a computer-controlled actuator to displace the sample attached to a force sensor, providing precise force measurements (13-15). While these setups are capable of accurately tracking actuator displacements, they often cannot precisely measure the sample’s deformation due to issues such as minor slippage at attachment points or alignment shifts as the tissue stretches. These challenges are particularly significant for smaller samples, making accurate stiffness measurements challenging without optical feedback. One solution is to mark the sample with landmarks and track its deformation using a digital camera (15, 16). Another approach involves mounting the extensometer on a microscope with adequate resolution to use cells as deformation landmarks (17-20). Recent extensometer setups for small biological samples often rely on specialized hardware, such as piezoelectric actuators or high-resolution linear stages, which can be prohibitively expensive for labs with limited funding or researchers exploring biomechanics on a smaller scale. For example, systems using SmarAct or Zaber actuators provide precise motion control but are typically priced beyond the reach of many academic labs. Fortunately, the decreasing costs of consumer-grade devices have made precise micro-actuators and micro-force sensors more accessible for these applications. However, software remains a significant hurdle. Many control libraries for specialized devices are proprietary and offer minimal functionality tailored to specific hardware. In addition, experimental setups frequently require separate software for each component, including the actuator, force sensor, and camera, which complicates system integration and operation. We present a Camelot system that overcomes these challenges by providing a low-cost micro-extensometer setup that is easy to assemble with minimal resources and technical expertise. The system is controlled by MorphoRobotX (15, 21-23) (www.MorphoRobotX.org), an integrated software environment for mechanical experimentation. MorphoRobotX seamlessly controls a wide range of actuators, force sensors, and cameras, and is able to utilize widely available components from consumer devices. An entire Camelot system, including an actuator, force sensor, control electronics, and camera, achieves precision in the range of approximately 5 µm. The open-source software is free to use and runs on a Linux desktop, with USB connectivity ensuring compatibility with modest hardware, including use with laptops. Its portability and suitability for high-resolution optical tracking under a microscope make Camelot an ideal tool for researchers in resource-limited settings or those pursuing exploratory biomechanics work. Results System overview The Camelot micro-extensometer system consists of three primary components: a force sensor with a sample attachment point, an actuator with a second attachment point to stretch the sample, and a camera to monitor deformation ( Fig. 1A; Suppl. Fig. 1 ). The force sensor, or load cell ( Suppl. Fig. 1C-D ), positioned on the linear motion stage ( Fig. 1A; Suppl. Fig. 1K ), is a parallel beam sensor commonly used in digital weighing scales, optimized for single-axis force measurement with minimal sensitivity to off-axis forces. Similar sensors were utilized by Bidhendi et al. (2020), and are available in various ranges, with a maximum force of several kilograms down to 10 grams. The 10g and 100g models in our system cost approximately 10 GBP each. The 10g sensor offers an accuracy of approximately 10 μN, making it highly suitable for precise biomechanical measurements on small samples ( Suppl. Fig. 1C-D ). For calibration, the force sensor is configured vertically using a custom 3D-printed holder for precise alignment and stability during force calibration ( Fig. 1B; Suppl. Fig. 1N, Q ). Phidgets, or "Physical Widgets" provide an accessible interface for hardware control, analogous to software widgets in a graphical user interface (24). Multiple Phidgets, including those for force sensor and actuator control, can be connected to a single Phidget Hub via USB ( Suppl. Fig. 1I ), facilitating computer integration. The sensors use a Phidgets Wheatstone Bridge to measure small resistance changes caused by deflection. With a DC input of 5–10 V, they generate an output voltage of 2–10 mV per input volt, directly proportional to the applied load. This low output voltage is subsequently amplified to a range suitable for an analog-to-digital converter (typically 0 to 5- or 10-volts DC). Consistent with Bidhendi et al. (2020), we use a Phidgets bridge amplifier Error! Bookmark not defined. power the sensor and amplify the signal ( Suppl. Fig. 1H ). The system's modular design, featuring a Wheatstone Bridge and compatibility with various load cells, including S-beam sensors from Futek (www.futek.com) (13, 19), allows seamless integration with diverse optical components, such as C-mount microscope cameras used in confocal setups. For these setups, the baseplate is securely mounted on the microscope stage, aligning the force sensor and sample with the optical path for simultaneous imaging and mechanical testing ( Fig. 1C ). The baseplate accommodates a Petri dish for sample hydration ( Fig. 1D ) and the setup enables confocal imaging to observe deformation at cellular resolution during mechanical testing ( Fig. 1E–F ). Figure 1 ( → next page): Fully integrated experimental setup for simultaneous mechanical measurement and imaging under a confocal microscope. ( A ) Overview of the assembled system, including the linear motion stage, the force sensor connected to the Wheatstone Bridge Phidget, with both connected to the VINT Hub Phidget to convert to USB. Electronic components are enclosed in a custom 3D-printed housing for protection and organization. The system interfaces with a computer via USB for real-time data acquisition and control. ( B ) Vertical configuration of the force sensor for calibration. The inset highlights the force sensor mounted in a custom 3D-printed holder with precise alignment for mechanical measurements. This configuration allows accurate force calibration while maintaining stability during operation. ( C ) Integration with a confocal microscope, with the baseplate securely mounted on the microscope stage to align the force sensor and sample with the optical path, enabling simultaneous imaging and mechanical testing. ( D ) Close-up of the sample mounted on the force sensor under the confocal microscope objective, positioned in a Petri dish for hydration and optical compatibility. ( E ) Confocal imaging of the sample under green fluorescence, showing alignment within the optical path. ( F ) Magnified view of the same sample under green fluorescence, illustrating finer details and secure alignment between the force sensor and the Wheatstone Bridge Phidget. The linear actuator in our system uses a stepper motor that drives a screw mechanism that moves a stage along linear rail ( Suppl. Fig. 1A, B ). Commonly used for precise movements in applications like CNC (Computer Numerical Control) machine control, these actuators are readily available in various sizes. Our setup features a compact actuator with a 1mm pitch screw, enabling 1mm of movement per full motor revolution. The stepper motor rotates in 1.8° increments, providing a movement precision of 5 μm per step, which meets the requirements of most experimental applications. For even finer control, the Phidgets stepper motor controller can subdivide these steps as needed ( Suppl. Fig. 1J ). The stepper motor follows the NEMA 11 standard, which specifies a 1.1-inch square faceplate, making it a compact and widely compatible choice. This standardization ensures easy assembly and interchangeability with components from different manufacturers. The uniform color coding of control wires further facilitates integration. The linear actuator selected for our setup has good build quality at a cost of approximately 50 GBP. It is durable, with no noticeable looseness in its mechanism, and has proven to be accurate and dependable for our experimental applications. The third component of the system is the camera, which integrates with the MorphoRobotX interface to capture deformation data. The software interface displays the menu for setup, calibration, and experiment execution, while a pop-up window shows force curves generated during stretching experiments, illustrating the force applied to the sample until rupture ( Fig. 2A, B ). We use a compact USB digital microscope, with models providing a resolution of 2592 × 1944 pixels available for approximately 100 GBP. At maximum magnification, the camera can visualize individual plant cells, but lower magnification is typically used to capture the full tissue section along with landmark dots, as demonstrated for onion epidermal cells and hypocotyl samples under tension ( Fig. 2C, D ). The camera operates independently of the micro-extensometer setup, allowing the system to be conveniently used under a conventional microscope when required. Our software interfaces with the digital microscope using the standard Linux webcam driver and is compatible with a range of smaller digital microscope cameras. Through Linux libraries such as OpenCV (opencv.org) and Micro-Manager (micro-manager.org), support is provided for various microscope cameras (typically C-mount), which are used in experiments requiring higher resolution or specialized imaging. Additional software libraries provided by camera manufacturers, such as the IDS-Peak library, are installed for some experiments to enable compatibility with specific cameras that are not accessible through OpenCV or Micro-Manager. Since MorphoRobotX uses a plugin-based system for camera drivers (processes), it is possible to integrate any camera that can be accessed through Linux libraries. Figure 2: Overview of the MorphoRobotX interface and samples under tension. ( A ) The pop-up window (CFM Data Viewer) relative to the Extensometer process, showing the force curve generated during a stretching experiment, illustrating the force applied to the sample until rupture. ( B ) The MorphoRobotX interface menu displays all the necessary setup, calibration, and experiment execution processes. ( C ) Onion epidermal layer cells captured through the setup camera, showing the sample under tension without visible deformation. ( D ) Etiolated 3 days old Col-0 hypocotyl, attached to Tough-Tags with visible landmarks marked on the sample. The sample is shown at its ultimate stress point just before rupture, illustrating deformation under tension. Scale bars: 1 mm (C); 2 mm (D). Basic setup with digital microscope The basic Camelot setup was equipped with a compact digital microscope to track landmarks on the sample and the Young’s modulus and breaking stress of etiolated Arabidopsis hypocotyls was measured. The experiments were conducted on wild-type (Col-0) and xxt1 xxt2 double mutant, which lacks xyloglucan in the cell walls (25). This allowed us to compare results obtained with Camelot to previously published data using alternative setups (25, 26). Prior to measurements, landmarks were applied to the surface of the hypocotyls using an India ink marker (Faber-Castell Pitt Artist Pen Brush, Black 199***). Before the experiment, three hypocotyls from each batch were imaged using a stereomicroscope (Leica M60) equipped with a digital camera (IC80 HD). These images were analyzed in ImageJ to measure the hypocotyl diameter, which was then used to calculate the cross-sectional surface area. Next, each hypocotyl was mounted between two transparent stickers (NIIMBOT Thermal Labels, Transparent Stickers, 14 × 30 mm). One sticker secured the apical portion of the hypocotyl, including the cotyledons, while the other held the root and basal portion of the hypocotyl. After positioning either the cotyledon or root pole of the hypocotyl between the two halves of a folded sticker, each sticker was punched using an office puncher and mounted onto the pins connected to the load cell or actuator. Hypocotyl images captured after each stretching step ( Suppl. Movie 1 ), along with corresponding force readings, were used to calculate Young’s modulus and ultimate stress for each sample ( Fig. 3A-C ). For each hypocotyl, a nearly linear section of the force-displacement curve was identified ( Fig. 3A ). This section spanned at least 50 steps, corresponding to a displacement of at least 0.25 mm, to minimize errors in strain assessment and allow for reliable calculations of material properties. Using ImageJ, we measured the distance between landmarks in images corresponding to the beginning and end of the selected linear portion of the force-displacement curve ( Fig. 3B-C ). The relative distance increment (representing the actual sample strain) and the corresponding increase in stress (calculated as the applied force divided by the cross-sectional surface area of the hypocotyl) were used to compute Young’s modulus. For the same samples, the ultimate stress at the point of sample rupture was determined from the force-displacement curves ( Fig. 3E ). The results of these analyses, performed with the basic Camelot setup, show consistent and statistically significant differences in Young’s modulus and ultimate stress between the etiolated hypocotyls of Arabidopsis Col-0 and the xxt1 xxt2 mutant ( Fig. 3D ) and are consistent with previous studies (25) where it was reported that the xxt1 xxt2 mutant exhibits altered mechanical properties in its cell walls, including reduced tensile strength and stiffness. Close examination of hypocotyl images captured during the measurements enabled us to distinguish between actual sample stretch and sample slippage from the grips (stickers), allowing for an accurate assessment of sample strain. This detailed imaging also facilitated a critical interpretation of the force-displacement curves. For instance, the curve shown in Fig. 3F suggests sample relaxation toward the end of the experiment. However, inspection of the images reveals that the observed decrease in force was primarily due to significant slippage of the hypocotyl from the stickers ( Fig. 3F-H ). Using etiolated hypocotyls of wild-type Arabidopsis , we conducted also a creep experiment to evaluate the time-dependent deformation of the samples ( Fig. 3I-J ). As anticipated, the rate of sample creep, assessed based on the positions of landmarks, decreased over time (blue curve in Fig. 3I ). However, it is important to note that the rate of grip displacement during the experiment was higher and increased rather than decreased in the later stages. This behavior was attributed to significant sample slippage from the grips (red curve in Fig. 3I ). Our results demonstrate that basic Camelot set up is sufficient to produce data showing mechanical differences between two genotypes using simple pen dots as landmarks to measure displacement. Figure 3 ( → next page): Mechanical properties and deformation analysis of etiolated Arabidopsis hypocotyls under tension and creep experiments. (A-C) Exemplary force-displacement curve ( A ), force plotted against actuator displacement or against the displacement assessed by landmark position ( B ) and corresponding hypocotyl images ( C ) obtained during the experiment, which terminated by hypocotyl breakage. Three red line segments in (A) mark the curve points to which the measurements shown in (B) and the first three hypocotyl images in (C) correspond, the last image in C was obtained immediately after the hypocotyl breakage. The force increase between the first two segments and the strain computed based on the first two images were used to compute Young’s modulus. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 2.09% for the first pair of images, and 0.88% for the second. Because of some slippage of hypocotyl from the tags, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e., 5.90% and 4.57%, respectively. Young’s modulus ( D ) and ultimate stress at breakage ( E ) were estimated for Col-0 and xxt1 xxt2 etiolated hypocotyls. Red lines within the boxes represent median; boxes delimit the first and third quantiles; whiskers extend from the box ends to adjacent values in the data as long as the most extreme values are within 1.5x interquartile range from the box end. Dots represent individual measurements. Hypocotyls of Col-0 (n=10) and xxt1 xxt2 (n=8 for modulus; n=7 for ultimate stress) differ significantly both in Young’s modulus (t-test; p=0.0031) and in ultimate stress (p=0.00007). ( F-H ) Exemplary force-displacement curve ( F ), force plotted against actuator displacement or against the displacement assessed by landmark position ( G ) and corresponding hypocotyl images ( H ) obtained during the experiment. During the last stage of the experiment (marked by red line segments) the grip displacement resulted mainly in sample slippage from the tags and virtually no hypocotyl strain. Three red line segments in F mark the curve points to which the measurements shown in G and three hypocotyl images in H correspond. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 0.28% for the first pair of images, and 0.36% for the second. Because of substantial slippage of hypocotyl from the stickers, in the region marked by black asterisks, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e. 5.19% and 4.17%, respectively. ( I-J ) Exemplary results of creep experiment using the basic setup. Displacement rates of landmarks (blue) or actuator grips (red) plotted over time ( I ) and corresponding hypocotyl images ( J ) are shown. Displacement rates were computed for 300 s time intervals, based on landmark positions (marked by white arrows in images) or actuator position recorded in .csv file. Setup using C-mount microscope camera A more accurate measure of deformation can be obtained by analyzing the cells or cell junctions as landmarks, using an inverted light or florescence microscope with a C-mount camera. For this setup, we placed Camelot on an inverted microscope (Axiovert 35M, Zeiss, Germany) with a C-mount camera (U3-3280SE, IDS, UK) to provide optical tracking. The IDS camera is just one example of a CCD camera that can be controlled by MorphoRobotX, synchronizing image capture with each step in the stepper motor. We stretched onion epidermal peels in both longitudinal and transverse directions ( Fig. 4 ) to test if similar results could be obtained to previously published data (15). Onion epidermal peels 4 mm wide, were prepared as described in Majda et al ., (2022). Longitudinally stretched samples were mounted so that the direction of stretch was axial along the tissue and transversely stretched samples were mounted so that the direction of stretch was circumferential. Distance between cell junctions was measured in ImageJ to accurately determine strain. Longitudinally stretched tissues reached a stress of 1.19 MPa at 10.6 % strain and withstood a maximum force of around 430000 µN before breakage. Transversely stretched tissues reached a stress of 2.08 MPa at 19.0 % strain and withstood a maximum force of around 300000 µN before breakage. At 10 % strain, longitudinally and transversely stretched samples had Young’s moduli of 11.23 MPa and 6.20 MPa, suggesting that the tissue is 1.94 times more stiff longitudinally than transversely, which is comparable with previous results (15). Strain was measured between two landmarks on the cells, instead of the position of the actuator, in the elastic region of the force/displacement curve. For the longitudinally stretched tissue, the distance in cell junctions increased from 147 µm to 175 µm, giving a strain of 19.0 %, whereas the actuator had moved from 730 mm to 1920 mm, giving an inaccurate strain of 95.5 %. For the transversely stretched tissue, the distance in cell junctions increased from 318.9 µm to 352.8 µm, giving a strain of 10.6 %, whereas the actuator had moved from 530 mm to 1110 mm, giving a strain of 163 %, more than an order of magnitude higher than distance measured from cell junctions. This suggests that displacement measurements without optical tracking can be highly inaccurate. We also found that the resolution and magnification are sufficient to capture mechanical failure at the cellular resolution. We could see that when a sample fails, the tissue separation occurred within a cell and propagated across the tissue. Thus, Camelot coupled with a top-mounted CCD can capture extensometer experiments with cellular resolution for accurate optical tracking. Figure 4. Onion epidermal peel deformation in extensometer experiments can be accurately measured using cell junctions. ( A-B ) Longitudinally stretched cell in a relaxed state ( A ) and under 10 % strain ( B ). Yellow line highlights cell junctions where distances were measured from. ( C ) Corresponding force-displacement curve for longitudinally stretched sample. ( D-E ) Transversely stretched cell in a relaxed state ( D ) and under 10 % strain ( E ). Yellow line highlights cell junctions where distances were measured from. ( F ) Corresponding force-displacement curve for transversely stretched sample. Scale bars: 20 µm. Confocal extensometer We used the confocal extensometer to analyze the deformation of epidermal cells from Arabidopsis leaf during stretching experiments. To facilitate tracking of the cell outlines, the plasma membrane marker line ( pUBQ10::acyl-YFP ) (27) was used. The samples were mounted onto Camelot’s extensometer arms using Tough-Tags and submerged in water within a small Petri dish to prevent desiccation. The setup was coupled with an upright Zeiss LSM 710 NLO confocal microscope, operated in single-photon mode. Confocal z-stack images were acquired at three stages: before stretching, during incremental deformation, and immediately prior to rupture ( Fig. 5, Suppl. Fig. 2, Suppl. Movie 2 ). These images were processed in MorphoGraphX (28) to compute the principal directions of deformation. Deformation was visualized at the cell centroids, with white lines indicating extension and red lines indicating contraction, with the lengths proportional to the amount. During the stretching experiments, cells exhibited anisotropic deformation, characterized by elongation along the axis of applied force and contraction perpendicular to it. This behavior is consistent with the concept of Poisson's ratio, which describes the ratio of transverse strain to axial strain in materials under stress. In plant cells, Poisson's ratio typically ranges from 0.18 to 0.30 (29), reflecting the lateral contraction that accompanies axial stretching, although that is for the cell wall itself, and here a cellular tissue is being stretched. Figure 5 : Cellular deformation analysis on Arabidopsis leaf . ( A ) Arabidopsis leaf sample attached to tags prior to stretching. Scale bar: 1 mm. ( B-C ) Confocal z-stack images of abaxial leaf cells before stretching (B) and at 9.5% strain or maximum deformation before rupture (C). Arrows indicate the stretching direction. ( D ) Heatmap of cell deformation of selected cells. Deformation crosses are calculated using MorphoGraphX, with white arms indicating extension and red arms indicating contraction, visualized at the cell centroids. Arrows indicate the stretching direction. B, C, and D share the same scale bar of 50 µm. ( E ) Boxplot showing longitudinal and transverse strain (%) of the selected cells in D. Longitudinal strain corresponds to the stretching direction, while transverse strain is perpendicular to it. The grey dashed line at 0% indicates no change in cell size. Discussion The Camelot system offers a simple and cost-effective solution for mechanical testing of small to medium-sized biological samples. It operates entirely on open-source software and is assembled from readily available consumer components. The cost and complexity of extensometer systems are largely influenced by the actuator choice. For instance, systems described by Schluck et al. (2013), Hofhuis et al. (2016) and Robinson et al. (2017) use SmarAct (www.smaract.com) piezo-based stick-slip positioners, which deliver nanometer resolution but have significant drawbacks. These high-quality positioners are costly, priced between 6,000–9,000 GBP depending on configuration, with long lead times and high sensitivity to dirt and shocks, making them complex to program and handle. A more affordable alternative involves high-precision screw-type linear stages from Thorlabs (14) or Zaber (30), costing around 1,350–2,000 GBP. While these actuators provide micrometer resolution, they remain expensive and may lack Linux driver support, as in the case of Thorlabs. Camelot uses a low-cost (50 GBP) screw drive actuator with an estimated 5 µm resolution sufficient for most sample testing. For example, achieving 5% deformation on a 5 mm sample would result in 50 steps. Although less precise than higher-end actuators, this resolution generally meets most experimental needs. Notably, relying solely on actuator position for tissue deformation measurement is impractical anyway due to sample slippage, rotation, and mounting tag flexibility, especially in smaller samples. Consequently, deformation needs to be measured through synchronized images, calculating distances between sample landmarks at each extension step. Thus, effective resolution depends on the accuracy of image-based landmark measurements rather than actuator precision. To demonstrate the utility of the device we performed experiments on living plant tissue in several configurations. In our most basic Camelot set up with a digital microscope, we were able to determine Young’s modulus and breaking stress of wild-type and xxt1 xxt2 double mutant etiolated Arabidopsis hypocotyls. We tracked deformation using landmark points marked on the hypocotyl using a permanent marker from synchronized images recorded by the software. We found that Young’s modulus for wild-type was around five times higher than xxt1 xxt2 , and that ultimate stress at breaking for wild-type was more than double that of xxt1 xxt2 . This demonstrates that a complete Camelot system costing under 500 GBP can measure similar biomechanical differences to those previously reported (25). We also used the system to perform creep experiments that showed significant creep in the first 5 minutes, that tapered off over time. This demonstrates that a budget Camelot system can be used to perform a range of the most common extensometer experiments. For labs that have access to microscopes with CCD cameras, we show that cellular level deformations can be tracked using mostly the same Camelot hardware. We used an IDS camera mounted to an inverted light microscope, but other cameras, microscope and fluorescence combinations can be also accommodated. Our data showed that onion epidermal peels are stiffer longitudinally than transversely, in line with previously published results (15). Camelot can also be combined with confocal microscopy (18-20) by adapting the mounting board. This can be used to measure cell deformations and response under stress. Arabidopsis leaf was placed under a measured strain and the deformation of individual cells in a tissue was determined using MorphoGraphX to analyze their shape change. A combination of Camelot with confocal microscopy allows for precise segmentation and tracking of deformation at the individual cell level by using cell boundaries. However, the slower imaging speed of confocal microscopy can lead to partial sample relaxation between steps. Additionally, images must be synchronized manually with the Camelot system, as most commercial confocal setups currently lack open software integration to directly trigger image acquisition. The Camelot system provides a low-cost, accessible, open-source solution that can be built from widely available consumer components, adaptable for various experimental needs. Several potential improvements could enhance the system's capabilities. While the low-cost actuator’s resolution is sufficient for many biomechanical measurements, a higher-end device might be beneficial in specific scenarios, such as oscillatory loading/unloading (31), or precise force applications where actuator backlash could interfere. High-quality actuators, such as SmarAct models, also produce less vibration, which could be an issue for confocal applications. The MorphoRobotX software already supports SmarAct and Zaber stages, with options to integrate other types of actuators that have Linux drivers. Given the importance of accurate deformation tracking, another key improvement could involve automated landmark recognition, potentially through AI-based methods. This feature would allow users to select landmarks at the start of the experiment, with the software tracking the landmarks as the sample stretches, enabling automatic calculation of deformation for each step. Additionally, a movable camera stage could keep landmarks within the field of view, facilitating greater zoom and higher resolution. However, implementing these enhancements would add considerable complexity and cost to the system. This work demonstrates how an affordable and adaptable extensometer like Camelot can open new possibilities for biomechanical research, making complex measurements more accessible to a wider range of laboratories and encouraging deeper exploration of the forces that drive biological growth and development. Methods The Camelot system is composed of modular 3D-printed components designed for mechanical testing of biological samples ( Suppl. Fig. 1K-Q , Suppl. Fig. 3 ). These components include the linear motion stage with a central hole for illumination, Petri plate positioning and actuator mounting ( Suppl. Fig. 3A, B, Suppl. Fig. 4B ), as well as a calibration stage with a central gap to securely hold the setup during calibration procedures ( Suppl. Fig. 3C, Suppl. Fig. 4E-F ). The arms of the micro-extensometer, equipped with pins for mounting samples using adhesive tape, ensure stable attachment to both the actuator and the sensor ( Suppl. Fig. 3D, E ). Additional structural components, such as the electronics box, protect the stepper controller and hub while providing sufficient ventilation and cable routing space ( Suppl. Fig. 3F-H, Suppl. Fig. 4C-D ). Collectively, these parts can be seamlessly assembled into a fully functional setup for calibration and micro-extensometer experiments ( Fig. 1 ), as shown in the detailed assembly steps in Fig. 6 , with the relative information for each component in Table 1 . The Camelot setup can be configured for different experimental needs. For example, the basic configuration with a digital microscope enables straightforward mechanical measurements with high-resolution imaging ( Suppl. Fig. 5A, B ). Alternatively, the system can be mounted on an inverted microscope for cellular resolution ( Suppl. Fig. 5C-E ). Each setup is optimized for its specific purpose, whether focusing on external deformation measurements or high-resolution observations of tissue and cellular behavior. Assembly of the system begins with connecting the Wheatstone Bridge, sensor, and actuator to the Phidgets Hub and ensuring proper data flow to the computer ( Fig. 6A-G ). The modular design allows mounting onto either a 3D-printed Camelot baseplate or a DIY plastic base created by drilling a plastic sheet to accommodate the setup ( Suppl. Fig. 5 ). Additionally, detailed 3D-printing parameters are provided in Table 2 , with .stl files available for download in Suppl. Data 1 , making the system accessible and reproducible. These files can be easily and inexpensively uploaded to online manufacturing services, allowing users to have the components professionally fabricated with minimal effort. Figure 6: Step-by-step assembly guide for integrating the components into a functional system. ( A ) Connect one end of the VINT cable to the Wheatstone Bridge Phidget (Phidgets DAQ1500) and the other end to Port 1 of the VINT Hub Phidget (Phidgets HUB0001). Ensure the cable is securely clicked into place. ( B ) Close-up of the VINT cable connection to the Wheatstone Bridge module, which transmits analog signals from the force sensor. ( C ) Plug the VINT cable from the Wheatstone Bridge into the VINT Hub Phidget (Port 1), allowing communication between the sensors and the computer. ( D ) Connect a second VINT cable tointo another port on the VINT Hub Phidget for the stepper motor. ( E ) Attach the USB cable to the USB output of the VINT Hub Phidget and connect the other end to the computer for data acquisition and control. ( F ) Connect the Wheatstone Bridge Phidget to the VINT Hub Phidget and ( G-H ) to the wiring harness of the force sensor using the screw terminals. Match the wiring colors to the terminal labels for proper signal and power alignment (e.g., red for power, black for ground, green and white for signal). ( G ) Close-up of the Wheatstone Bridge Phidget’s terminals with all wires securely fastened using a small flathead screwdriver. Check if wires are tightly clamped for stable signal transmission. ( H ) Attach the force sensor (Phidgets 3133_0 Micro Load Cell) to the Wheatstone Bridge harness. Use a custom mount to position the force sensor correctly for force measurements. ( I ) Ensure the wiring harness for the force sensor is properly routed, avoiding sharp bends to prevent wire damage. ( J ) Mount the force sensor on its designated holder or fixture to align it with the experimental setup. ( K ) Plug the VINT cable from the VINT hub into the stepper motor Phidget. ( L ) Prepare the power and motor control wires by stripping the ends to expose the metal conductors for secure attachment. ( M ) Stepper motor Phidget (Phidgets STC1002_0). ( N ) Securely attach the stepper motor wires to the motor controller, ensuring the wires are inserted into the correct terminals (A+, A-, B+, B-) to match the motor coil configuration. ( O ) Plug the VINT cable from the VINT hub into the motor controller. ( P ) Connect the motor controller to the power supply ensuring polarity is correct (red for positive, black for ground). ( Q ) Mount the linear motion stage (THK KR20 Linear Stage) by aligning the mounting holes of the stage and securing the motor controller using screws. ( R ) Power supply, (Mean Well GST25A05-P1J) 12VDC, 2 amps. ( S ) Assemble all components onto the custom 3D-printed "Camelot" baseplate. Use screws to secure the VINT Hub, Wheatstone Bridge, motor controller, and linear motion stage to the baseplate. Check if all components are stable and properly aligned. Arrows in the figure illustrate the sequence of connections and the flow of data and power across the system. Scale bar: 30 mm. The linear motor stage of the Camelot system integrates with advanced imaging platforms, including confocal, two-photon, and epifluorescence microscopes, to enable simultaneous mechanical measurements and high-resolution imaging. As shown in Suppl. Fig. 6 , the force sensor and sample holder align within the optical path, ensuring positioning under the confocal objective lens ( Suppl. Fig. 6A-B ). The stability provided by the "Camelot" baseplate supports reliable imaging and mechanical testing without interference from sensor wiring ( Suppl. Fig. 6C-D ). The system demonstrates versatility in capturing fluorescence signals at different wavelengths, using green and blue laser illumination to produce clear, interference-free images of the sample during mechanical experiments ( Suppl. Fig. 6E–H ). This capability allows detailed observation of sample behavior under mechanical stress. When used with an inverted microscope, the Camelot system maintains its adaptability. As shown in Suppl. Fig. 7 , the baseplate is securely mounted on adjustable brackets, aligning the force sensor and other components with the optical path ( Suppl. Fig. 7A–C ). Samples positioned within a Petri dish are located for simultaneous imaging and force measurements, while the modular design ensures accessibility and alignment of all components ( Suppl. Fig. 7D–H ). Control software The Camelot system is controlled by MorphoRobotX (www.MorphoRobotX.org) ( Fig. 2 ), which serves as the control software for the Cellular Force Microscope (22, 32), and various extensometer setups (15, 21, 23). The graphical user interface for MorphoRobotX is modeled after MorphoGraphX (28), and users are encouraged to familiarize themselves with MorphoGraphX to better understand its layout and functionality. As with MorphoGraphX, MorphoRobotX organizes tasks into processes, which manage key operations such as stage movement, sample stretching, calibration, and parameter settings. These processes also represent hardware components (drivers), including the camera, actuator, and force sensor, and come pre-configured with experimental defaults. Additional hardware elements (actuators, cameras, acquisition devices) can be added via a plug-in system that allows the incorporation of additional processes. Throughout each session, MorphoRobotX creates logs, recording data such as forces, stage positions, and camera images which are synchronized with extensometer steps as the experiment progresses. Experimental Workflow The experimental workflow for the Camelot system covers the key steps required for conducting mechanical testing and imaging experiments. It begins with calibrating the system's hardware to achieve reliable measurements, followed by preparing the samples with appropriate mounting and hydration methods. Finally, the samples are stretched using either manual or automated procedures, allowing for accurate force application and imaging. This workflow is adaptable to various experimental setups and research objectives, providing flexibility while maintaining consistency in data collection. System calibration To achieve accurate force measurements with the load cell, the sensor’s gain must be calibrated to accurately convert voltage readings into force. We encourage users to do this periodically, and to verify the calibration before and after experiments to ensure the sensor is not damaged. Measure and calculate the weight of a known load : Use an analytical balance to measure the weight of the chosen calibration object ( e.g. , a screw, nut, or bolt) multiple times to minimize variability. Calculate the average weight by summing all measurements and dividing by the number of measurements. Convert the weight into force using the formula , where , with 1 gram equivalent to 9806.65 µN. Record this theoretical force as your reference value. Verify hardware defaults and initialize components : Before proceeding, confirm that the defaults for the sensor, actuator, and camera are correctly configured under "Tools/MorphoRobotX/Experiment Defaults”. Begin by initializing the actuator through "Tools/MorphoRobotX/Actuator/Phidgets Positioner". Then, initialize the sensor by double-clicking on "Tools/MorphoRobotX/Sensors/Phidgets Sensor" to confirm that MorphoRobotX can communicate effectively with the hardware. If successful, nothing will happen, but if not, an error box will pop up. Prepare the sensor and set the offset : Once the hardware is properly initialized, move Camelot and the load cell to a vertical position using the 3D-printed calibration stand or any stable L-bracket to securely support the load cell. Open “Tools/MorphoRobotX/Sensors/Set Offset” and run the Set Offset process with the sensor alone, ensuring no weight is on the load cell. This action zeroes the sensor, removing any residual force readings. Then navigate to “Tools/MorphoRobotX/Experiment/Monitor Force”, activate the Monitor Force process to display real-time force measurements and confirm that the displayed force values are around zero. A dd the weight and check the force : Place the known weight on the load cell. Use “ Tools/MorphoRobotX/Experiment/Monitor Force ” to observe the force value measured by the sensor. Use the “ Tools/MorphoRobotX/Sensors/Calibrate Force ” process with the previously calculated value for the reference weight in the "Target Force" parameter. This will calculate the correct sensor gain and write it to the "Sensor Gain" parameter of the force sensor process. Mitigate environmental noise : If fluctuations are observed in the force readings during calibration or use, consider addressing potential environmental factors. Noise can result from temperature changes, vibrations, or electromagnetic interference. To minimize these effects, ground the experimental setup and, if necessary, place the load cell and related components inside an isolation box. Additionally, use a vibration isolation table with pneumatic supports, which helps dampen external mechanical vibrations. These measures stabilize the sensor's performance and ensure the reliability of its readings. Validate the calibration and document : After calibration, remove the weight from the load cell and return Camelot to a horizontal position. Use “Tools/MorphoRobotX/Experiment/Monitor Force” to check the force. Since the weight of the sensor will affect the force, rerun “Tools/MorphoRobotX/Sensors/Set Offset” to zero it in the horizontal position. Document the final gain value (from the "Sensor Gain" parameter on the sensor process) for future reference. A large change in this value could indicate damage to the sensor. The sensor is now ready for precise force quantification in experimental applications. Sample preparation Sample preparation for experiments using the Camelot system involves preparing adhesive tags as mounting points for tissue samples, selecting or dissecting samples according to the experimental design, and attaching the tissue ends to the tags. Artificial landmarks can be added to the samples to track deformation during testing. Hydration is maintained throughout to minimize changes in tissue properties. The prepared samples are mounted on the Camelot setup and aligned appropriately for stretching, with attention to uniform tension and proper positioning. Prepare the adhesive tags : Before starting the experiment, prepare adhesive tags such as Tough-Tags (Diversified Biotech, Cat. No. TTLC-1000) or NIIMBOT Thermal Transparent Stickers. Punch holes in the tags using a hole puncher, making sure the holes are appropriately sized and positioned for mounting on the Camelot setup pins. If needed, apply an adhesive scale bar directly onto the tags, especially for small samples. Alternatively, if the adhesive tape has a known dimension (e.g., the Tough-Tags width of 12.7 mm), this can serve as a built-in scale bar. Select or dissect the tissue : Once the adhesive tags are prepared, select or dissect the tissue sample according to the experimental requirements. For small samples, such as Arabidopsis hypocotyls or epidermal peels, use the prepared adhesive tags for mounting. For larger or thicker samples, such as pine or elm hypocotyls, consider using stronger adhesion methods, such as gluing the sample ends into small rubber tubes that can be secured with clamps (33). Mount the tissue ends onto adhesive tags : Attach the ends of the tissue sample to the prepared adhesive tags. Fold each tag in half over the tissue to ensure full adhesion and even distribution of tensile force. Press the tags firmly to prevent slippage during the experiment. Verify that the tissue is aligned centrally within the tags for consistent stretching. Apply landmarks : To track tissue deformation, put landmarks on the tissue using a very thin, soft, waterproof marker, such as a fine eyeliner or permanent marker. These landmarks will assist in measuring changes in length and distance during stretching. Make sure that the application of the markers does not damage or deform the tissue ( Fig. 2C ). Prevent dehydration : To prevent dehydration-related changes in tissue properties, place the prepared sample in water temporarily while additional samples are being prepared. Alternatively, if the sample is to be stretched immediately, proceed with mounting and stretching promptly to minimize dehydration. Mount the sample on the Camelot setup : Transfer the prepared sample to the Camelot setup. Depending on the preparation method, either float the sample on the water surface of a water-filled plate before mounting or directly mount it onto the pins if stretching immediately without additional hydration. Verify that the adhesive tags are positioned correctly for secure attachment. Secure the sample on the pins : Use forceps to handle the sample and carefully position the adhesive tags onto the pins or bolts of the Camelot setup. Push the tags firmly down onto the pins to confirm they are securely mounted. If the sample is in a water-filled plate, confirm that it is fully submerged and stabilized for the stretching process. Align the sample for stretching : Adjust the actuator of the Camelot setup using "Tools/MorphoRobotX/Actuators/Move Actuator" to align the sample properly. Check whether the tissue is straight to help spread the tension evenly. Verify that the adhesive tags are securely mounted on the pins and that the sample is free from twisting or bending. Once the alignment is complete, the sample is now ready to be stretched. Stretching The system can be operated either manually or automatically. Manual operation is often used to evaluate system behavior and determine key parameters, such as the required step size and the stabilization time between steps. Automatic operation enables precise stretching, allowing the system to record each step across the range of applied forces while synchronizing images captured by the camera or microscope. Manual stretching Capture an initial image : Capture an image of the sample in its relaxed state. Ensure that the sample is well-aligned, and the scale bar and any landmarks are visible in the image. Stretch the sample : Stretch the sample incrementally by moving the actuator using "Tools/MorphoRobotX/Actuators/Move Actuator". Enter the desired distance for each stretch in the "Move Measure" parameter. Monitor the resulting force after each stretch using "Tools/MorphoRobotX/Experiment/Monitor Force" for consistent application of tension. Allow the force to stabilize : After each actuator movement, allow the force to stabilize before further stretching. Capture images at each stretching point : If a camera is integrated, open the camera interface through "Tools/MorphoRobotX/Camera/OpenCV Camera". Use the "Take Snapshot" button in the camera window to capture images at each stretching point, ensuring documentation of the sample's deformation throughout the experiment. Automated stretching Activate the camera : Open the camera interface by double-clicking the appropriate camera type in "Tools/MorphoRobotX/Camera" folder. Check whether the camera feed is active, and the sample is in focus to capture the sample's deformation throughout the experiment. Configure automated stretching : Initiate the automated stretching process by opening "Tools/MorphoRobotX/Experiment/Extensometer". Set the total distance to be covered during the experiment using the "Distance" parameter. Define the step size with the “Step Size” parameter. Adjust step sizes based on sample characteristics. Smaller step sizes yield more data but increase experiment duration, while larger step sizes may risk sample damage. Configure the wait time : If required, adjust the "Wait Time" parameter to change the amount of time to wait for force stabilization between steps. If the system is being used with a confocal microscope or a camera that is not integrated with MorphoRobotX, set this time to -1 and the system will pop-up a window and wait for confirmation that the image has been captured before proceeding to the next step. Creep experiments : For creep experiments, specify the starting force threshold using the "Creep Threshold" parameter. The system will stretch the sample at a constant rate until the specified force is reached, then make steps periodically as required to maintain that force. For elasticity experiments the "Creep Threshold" to 0, which is the default. Start the stretching experiment : Begin the experiment by double-clicking "Tools/MorphoRobotX/Experiment/Extensometer". Real-time force readings and a live camera feed will display, and snapshots of the stretching sample will be saved automatically to disk. Return to the starting position : Once the total distance set for the experiment is reached, the actuator will automatically return to its starting position, completing the stretching cycle. Cancel if necessary : If it is required to interrupt the experiment to stop the stretching, press the "Stop" button in the upper right-hand side of the MorphoRobotX window. Force readings and snapshots of the stretching sample will be saved automatically to disk. Use "Tools/MorphoRobotX/Actuators/Move Actuator" to manually return the actuator to its starting position and reset the setup as needed. Data analysis Each automated extensometer experiment produces three sets of files, an Extensometer .csv file, a Snapshots folder with camera images for each step in the experiment, and an MRXlog . csv file containing raw data from the sensor and actuator. These are named with a date and time stamp of when the experiment started. The Extensometer file has columns Position (nm), Force (µN) and Time (µs) data for each step of the extensometer experiment. Each actuator step is associated with a snapshot and a corresponding force value. For manual stretching, data is manually collected from both the relaxed and stretched states. Landmarks from snapshots or confocal scans, such as cell junctions, are used to measure linear distance changes. Confocal data segmented using MorphoGraphX (MGX) can provide information on area or volume changes. A force curve can be generated by plotting actuator steps against force. To determine stress, two points within the elastic region of the force curve are selected, and their corresponding actuator steps are analyzed. Snapshots from these steps are used to measure landmark displacements, such as cell junctions or applied markers, which are then used to calculate strain. Mechanical properties are assessed by calculating stress and strain from force-displacement data recorded during the extensometer experiment. Stress ( ) is calculated by dividing the applied force ( ) by the sample’s cross-sectional area ( ). For cylindrical samples, such as hypocotyls, stems, or roots, the cross-sectional area is determined using the formula , where is the radius. The radius can either be calculated by measuring the diameter of the sample under tension with the integrated digital microscope camera and halving it or by preparing cross-sections and averaging the radius of samples of the same genotype. For non-cylindrical samples, such as leaves, sepals, or epidermal peels, cross-sectional areas require different approaches. Cross-sections can be obtained to calculate an average area for the specific sample type. Alternatively, for approximate calculations, the known or measured thickness of the sample can be combined with its width to estimate the cross-sectional area as . Strain ( ), expressed as a percentage, represents the relative elongation of the sample and is calculated as . Here, is the change in length, determined as the difference between the stretched length just before rupture and the initial length under tension ( ) (34). Analysis typically focuses on the linear elastic region of the stress-strain curve, where deformation is proportional to the applied force, following Hooke’s Law ( ), with as the elastic modulus (34). This part of the curve avoids plastic deformations, capturing reversible deformations where the sample returns to its original shape upon force removal. Strains are typically limited to below 10-20% so that they remain within the range that would normally be experienced by the plant cell wall. These can be much higher when measuring failure stress or plasticity. By isolating the linear elastic region, a single number for the elastic modulus can be calculated for each sample. Parts list Table 1: Components and costs for the Camelot setup. A detailed breakdown of the parts required for the Camelot setup, excluding 3D-printed components. Costs are provided in GBP (£). Part Make Model Cost (GBP) Linear actuator with motor Befenybay 50mm NEMA11 T6x1 47 Camera (2592x1944) Celestron 44308 97 10g load cell Dongguan Science & Tech 10g 8+16 1 100g load cell Phidgets 139_0 8 Stepper motor controller (8A) Phidgets STC1002_0 82 Wheatstone Bridge Phidgets DAQ1500_0 30 VINT Hub Phidgets HUB0001 30 Power supply (12Vdc, 2A) Phidgets 3025_0 12 Mini-USB Cable (180cm) Phidgets 3018_0 2 10cm cable (x2) Phidgets 3003_0 3 2-axis manual stage 2 Hyuduo 40x40 90 3D-printed components 3 Generic - 9 Nuts, bolts, small hardware Generic - 20 Total 438 1 Ordered from Alibaba, shipping (16 GBP) costs more than a sensor (10 GBP), best to order multiples. 2 This stage is optional but helps to position the sample precisely. Any suitable stage can be used, for example one recycled from an old light microscope. 3 A home-made plastic base can also be used as an alternative to 3D-printing. Table 2: 3D-printed components and costs for the Camelot setup. A detailed breakdown of the 3D-printed components required for the Camelot setup ( Suppl. Data 1 ). Costs are provided in GBP. Component Material Filament Infill (%) Supports Rotation (°) Filament use (g) Printing time (h) Cost (GBP) Linear motor stage PETG Matte black, matte white 20 Build plate - 88.3 3.2 2.36 Calibration stand PETG Matte black 20 Build plate - 86.5 3 2.30 Electronics box PLA Matte black 20 Everywhere, tree - 102 3.6 2.04 Box lid PLA Matte black 20 Build plate Y: 180 121.2 3.7 2.15 Actuator arm PETG Matte black 40 Everywhere, tree Y: 180 3.1 0.5 0.09 Sensor arm PETG Matte black 80 Everywhere, normal - 0.7 0.3 0.02 Total 401.7 14.5 8.96 Declarations Author Contribution Conceptualization: RSS, DK, MM. Methodology: NT, WW, RKB, RSS, DK, MM. Investigation: NT, WW, RKB, AM, AC, NA, RSS, DK, MM. Formal analysis: NT, RKB, AM, RSS, DK, MM. Writing: NT, RKB, RSS, DK, MM. Funding acquisition: NT, RSS, DK, MM. Supervision: RSS, DK, MM. Acknowledgement Authors thank the Cellular Imaging Facility (CIF) at the University of Lausanne for support with confocal microscopy. References Cosgrove DJ. Wall extensibility: its nature, measurement and relationship to plant cell growth. New Phytol. 1993;124(1):1-23. Bidhendi AJ, Geitmann A. Relating the mechanics of the primary plant cell wall to morphogenesis. Journal of experimental botany. 2016;67(2):449-61. Lockhart JA. An analysis of irreversible plant cell elongation. Journal of Theoretical Biology. 1965;8(2):264-75. Cosgrove DJ. Loosening of plant cell walls by expansins. Nature. 2000;407(6802):321-6. Schopfer P. Biomechanics of plant growth. American journal of botany. 2006;93(10):1415-25. Cosgrove DJ. Enzymes and other agents that enhance cell wall extensibility. Annual review of plant biology. 1999;50(1):391-417. Cosgrove DJ, Jarvis MC. Comparative structure and biomechanics of plant primary and secondary cell walls. Frontiers in plant science. 2012;3:204. Liu S, Strauss S, Adibi M, Mosca G, Yoshida S, Ioio RD, et al. Cytokinin promotes growth cessation in the Arabidopsis root. Current Biology. 2022;32(9):1974-85. e3. Bidhendi AJ, Geitmann A. Methods to quantify primary plant cell wall mechanics. Journal of Experimental Botany. 2019;70(14):3615-48. Alonso Baez L, Bacete L. Cell wall dynamics: novel tools and research questions. Journal of Experimental Botany. 2023;74(21):6448-67. Trinh DC, Alonso-Serra J, Asaoka M, Colin L, Cortes M, Malivert A, et al. How Mechanical Forces Shape Plant Organs. Curr Biol. 2021;31(3):R143-r59. Cleland R. Cell wall extension. Annual review of plant physiology. 1971;22(1):197-222. Hofhuis H, Moulton D, Lessinnes T, Routier-Kierzkowska AL, Bomphrey RJ, Mosca G, et al. Morphomechanical Innovation Drives Explosive Seed Dispersal. Cell. 2016;166(1):222-33. Bidhendi AJ, Zamil MS, Geitmann A. Assembly of a simple scalable device for micromechanical testing of plant tissues. Methods in Cell Biology. 160: Elsevier; 2020. p. 327-48. Majda M, Trozzi N, Mosca G, Smith RS. How Cell Geometry and Cellular Patterning Influence Tissue Stiffness. Int J Mol Sci. 2022;23(10). Geitmann A, Ortega JK. Mechanics and modeling of plant cell growth. Trends in plant science. 2009;14(9):467-78. Harris AR, Bellis J, Khalilgharibi N, Wyatt T, Baum B, Kabla AJ, et al. Generating suspended cell monolayers for mechanobiological studies. Nature protocols. 2013;8(12):2516-30. Schluck T, Nienhaus U, Aegerter-Wilmsen T, Aegerter CM. Mechanical Control of Organ Size in the Development of the Drosophila Wing Disc. PLoS ONE. 2013;8(10):e76171. Robinson S, Huflejt M, Barbier De Reuille P, Braybrook SA, Schorderet M, Reinhardt D, et al. An Automated Confocal Micro-Extensometer Enables in Vivo Quantification of Mechanical Properties with Cellular Resolution. The Plant Cell. 2017;29(12):2959-73. Chen S, Burda I, Jani P, Pendrak B, Silberstein MN, Roeder AH. Fibrous Network Nature of Plant Cell Walls Enables Tunable Mechanics for Development. bioRxiv. 2024:2024.10. 09.617478. Mollier C, Skrzydeł J, Borowska-Wykręt D, Majda M, Bayle V, Battu V, et al. Spatial consistency of cell growth direction during organ morphogenesis requires CELLULOSE SYNTHASE INTERACTIVE1. Cell Reports. 2023;42(7):112689. Majda M, Sapala A, Routier-Kierzkowska AL, Smith RS. Cellular Force Microscopy to Measure Mechanical Forces in Plant Cells. Methods Mol Biol. 2019;1992:215-30. Baba AI, Lisica L, Atakhani A, Aryral B, Bogdziewiez L, Erguvan Ö, et al. Rhamnogalacturonan-II dimerization deficiency impairs the coordination between growth and adhesion maintenance in plants. bioRxiv. 2024:2024.11. 26.625362. Greenberg S, Fitchett C, editors. Phidgets: easy development of physical interfaces through physical widgets. Proceedings of the 14th annual ACM symposium on User interface software and technology; 2001. Cavalier DM, Lerouxel O, Neumetzler L, Yamauchi K, Reinecke A, Freshour G, et al. Disrupting Two Arabidopsis thaliana Xylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component. The Plant Cell. 2008;20(6):1519-37. Sowinski EE, Westman BM, Redmond CR, Kong Y, Olek AT, Olek J, et al. Lack of xyloglucan in the cell walls of the Arabidopsis xxt1/xxt2 mutant results in specific increases in homogalacturonan and glucomannan. The Plant Journal. 2022;110(1):212-27. Willis L, Refahi Y, Wightman R, Landrein B, Teles J, Huang KC, et al. Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche. Proceedings of the National Academy of Sciences. 2016;113(51):E8238-E46. Strauss S, Runions A, Lane B, Eschweiler D, Bajpai N, Trozzi N, et al. Using positional information to provide context for biological image analysis with MorphoGraphX 2.0. eLife. 2022;11. Wei C, Lintilhac PM, Tanguay JJ. An insight into cell elasticity and load-bearing ability. Measurement and theory. Plant Physiology. 2001;126(3):1129-38. Blösch R, Plaza-Wüthrich S, Barbier de Reuille P, Weichert A, Routier-Kierzkowska A-L, Cannarozzi G, et al. Panicle angle is an important factor in tef lodging tolerance. Frontiers in plant science. 2020;11:61. Hayot CM, Forouzesh E, Goel A, Avramova Z, Turner JA. Viscoelastic properties of cell walls of single living plant cells determined by dynamic nanoindentation. Journal of experimental botany. 2012;63(7):2525-40. Routier-Kierzkowska A-L, Weber A, Kochova P, Felekis D, Nelson BJ, Kuhlemeier C, et al. Cellular Force Microscopy for in Vivo Measurements of Plant Tissue Mechanics. Plant Physiology. 2012;158(4):1514-22. Saxe F, Weichold S, Reinecke A, Lisec J, Döring A, Neumetzler L, et al. Age effects on hypocotyl mechanics. PLoS One. 2016;11(12):e0167808. Niklas KJ. Plant biomechanics: an engineering approach to plant form and function: University of Chicago press; 1992. Additional Declarations No competing interests reported. Supplementary Files SupplementaryData.zip SupplementaryMovie1.avi SupplementaryMovie2.gif SupplementaryMaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 16 Feb, 2025 Reviews received at journal 14 Feb, 2025 Reviews received at journal 04 Feb, 2025 Reviews received at journal 01 Feb, 2025 Reviewers agreed at journal 28 Jan, 2025 Reviewers agreed at journal 25 Jan, 2025 Reviewers agreed at journal 23 Jan, 2025 Reviewers invited by journal 23 Jan, 2025 Editor assigned by journal 15 Jan, 2025 Submission checks completed at journal 15 Jan, 2025 First submitted to journal 14 Jan, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5828617","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Method Article","associatedPublications":[],"authors":[{"id":402103689,"identity":"e78ea055-e689-475c-b098-f6b842885db8","order_by":0,"name":"Nicola Trozzi","email":"","orcid":"","institution":"John Innes Centre","correspondingAuthor":false,"prefix":"","firstName":"Nicola","middleName":"","lastName":"Trozzi","suffix":""},{"id":402103690,"identity":"dcb490a6-6309-4c2c-a9db-ba644eba2ed5","order_by":1,"name":"Wiktoria Wodniok","email":"","orcid":"","institution":"University of Silesia","correspondingAuthor":false,"prefix":"","firstName":"Wiktoria","middleName":"","lastName":"Wodniok","suffix":""},{"id":402103691,"identity":"b5fb340a-6810-497b-9199-f0359ce1f432","order_by":2,"name":"Robert Kelly-Bellow","email":"","orcid":"","institution":"John Innes Centre","correspondingAuthor":false,"prefix":"","firstName":"Robert","middleName":"","lastName":"Kelly-Bellow","suffix":""},{"id":402103692,"identity":"f33c9797-ccd9-45c5-af9a-e7f39e212f2e","order_by":3,"name":"Andrea Meraviglia","email":"","orcid":"","institution":"University of Lausanne","correspondingAuthor":false,"prefix":"","firstName":"Andrea","middleName":"","lastName":"Meraviglia","suffix":""},{"id":402103693,"identity":"bf93f48f-940d-45c0-8b0b-013cd00a6448","order_by":4,"name":"Aurore Chételat","email":"","orcid":"","institution":"University of Lausanne","correspondingAuthor":false,"prefix":"","firstName":"Aurore","middleName":"","lastName":"Chételat","suffix":""},{"id":402103694,"identity":"d12be554-558c-42d4-a10c-47ec9a648e0e","order_by":5,"name":"Nova Adkins","email":"","orcid":"","institution":"John Innes Centre","correspondingAuthor":false,"prefix":"","firstName":"Nova","middleName":"","lastName":"Adkins","suffix":""},{"id":402103695,"identity":"91413391-b06f-4742-8c74-03fb422ef2ec","order_by":6,"name":"Richard S Smith","email":"","orcid":"","institution":"John Innes Centre","correspondingAuthor":false,"prefix":"","firstName":"Richard","middleName":"S","lastName":"Smith","suffix":""},{"id":402103696,"identity":"da41fac0-39b0-42a0-82ad-94dfae6b70d7","order_by":7,"name":"Dorota Kwiatkowska","email":"","orcid":"","institution":"University of Silesia","correspondingAuthor":false,"prefix":"","firstName":"Dorota","middleName":"","lastName":"Kwiatkowska","suffix":""},{"id":402103697,"identity":"ae1470b7-6af3-4c1d-b9c9-14b1bde8d8c4","order_by":8,"name":"Mateusz Majda","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYJCDBAmGCgYGNnYGBmb8ChHSQC1ngFqYSdDCIMHYBhHAq0W3/fzBxzx/6oCMAw9v/Jx3OI+PmYHxcwEeLWZnkpmNedvYgIyEZMvebYeLgQ5jlp6BT8uBZDZp3gYeICMhTYJ32+HENmagd3jwaTn/mP03zx8JIONBmuTfOcRouZEMVMBmAGQkpAGtI0rLY2PJuW0JPGY3HiRbyxxLB2phbJbG77DEhx/e/KmTMzufk3jzTY114vz25oOf8WmBAaAangQom7GBCA1gwH6AWJWjYBSMglEwwgAAcaNFdX9b8sYAAAAASUVORK5CYII=","orcid":"","institution":"University of Lausanne","correspondingAuthor":true,"prefix":"","firstName":"Mateusz","middleName":"","lastName":"Majda","suffix":""}],"badges":[],"createdAt":"2025-01-14 16:08:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5828617/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5828617/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":73843953,"identity":"2f9caab7-1b04-4db2-a411-9267444c255d","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":637200,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFully integrated experimental setup for simultaneous mechanical measurement and imaging under a confocal microscope. \u003c/strong\u003e(\u003cstrong\u003eA\u003c/strong\u003e) Overview of the assembled system, including the linear motion stage, the force sensor connected to the Wheatstone Bridge Phidget, with both connected to the VINT Hub Phidget to convert to USB. Electronic components are enclosed in a custom 3D-printed housing for protection and organization. The system interfaces with a computer via USB for real-time data acquisition and control. (\u003cstrong\u003eB\u003c/strong\u003e) Vertical configuration of the force sensor for calibration. The inset highlights the force sensor mounted in a custom 3D-printed holder with precise alignment for mechanical measurements. This configuration allows accurate force calibration while maintaining stability during operation. (\u003cstrong\u003eC\u003c/strong\u003e) Integration with a confocal microscope, with the baseplate securely mounted on the microscope stage to align the force sensor and sample with the optical path, enabling simultaneous imaging and mechanical testing. (\u003cstrong\u003eD\u003c/strong\u003e) Close-up of the sample mounted on the force sensor under the confocal microscope objective, positioned in a Petri dish for hydration and optical compatibility. (\u003cstrong\u003eE\u003c/strong\u003e) Confocal imaging of the sample under green fluorescence, showing alignment within the optical path. (\u003cstrong\u003eF\u003c/strong\u003e) Magnified view of the same sample under green fluorescence, illustrating finer details and secure alignment between the force sensor and the Wheatstone Bridge Phidget.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/bdfa1a39d4201d76f43ee5d0.png"},{"id":73843952,"identity":"e863ffbd-7b44-44aa-9f8c-ec987812cd43","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":294327,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOverview of the MorphoRobotX interface and samples under tension. \u003c/strong\u003e(\u003cstrong\u003eA\u003c/strong\u003e)\u003cstrong\u003e \u003c/strong\u003eThe pop-up window (CFM Data Viewer) relative to the Extensometer process, showing the force curve generated during a stretching experiment, illustrating the force applied to the sample until rupture. (\u003cstrong\u003eB\u003c/strong\u003e) The MorphoRobotX interface menu displays all the necessary setup, calibration, and experiment execution processes. (\u003cstrong\u003eC\u003c/strong\u003e) Onion epidermal layer cells captured through the setup camera, showing the sample under tension without visible deformation. (\u003cstrong\u003eD\u003c/strong\u003e) Etiolated 3 days old Col-0 hypocotyl, attached to Tough-Tags with visible landmarks marked on the sample. The sample is shown at its ultimate stress point just before rupture, illustrating deformation under tension. Scale bars: 1 mm (C); 2 mm (D).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/529d009b1b377e0c1c7e064d.png"},{"id":73843954,"identity":"15e46c4a-f146-470c-baf5-fc5cbeed1111","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":243084,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMechanical properties and deformation analysis of etiolated Arabidopsis hypocotyls under tension and creep experiments. (A-C) \u003c/strong\u003eExemplary force-displacement curve (\u003cstrong\u003eA\u003c/strong\u003e), force plotted against actuator displacement or against the displacement assessed by landmark position (\u003cstrong\u003eB\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eC\u003c/strong\u003e) obtained during the experiment, which terminated by hypocotyl breakage. Three red line segments in (A) mark the curve points to which the measurements shown in (B) and the first three hypocotyl images in (C) correspond, the last image in C was obtained immediately after the hypocotyl breakage. The force increase between the first two segments and the strain computed based on the first two images were used to compute Young’s modulus. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 2.09% for the first pair of images, and 0.88% for the second. Because of some slippage of hypocotyl from the tags, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e., 5.90% and 4.57%, respectively. Young’s modulus (\u003cstrong\u003eD\u003c/strong\u003e) and ultimate stress at breakage (\u003cstrong\u003eE\u003c/strong\u003e) were estimated for Col-0 and \u003cem\u003exxt1 xxt2\u003c/em\u003e etiolated hypocotyls. Red lines within the boxes represent median; boxes delimit the first and third quantiles; whiskers extend from the box ends to adjacent values in the data as long as the most extreme values are within 1.5x interquartile range from the box end. Dots represent individual measurements. Hypocotyls of Col-0 (n=10) and \u003cem\u003exxt1 xxt2\u003c/em\u003e(n=8 for modulus; n=7 for ultimate stress) differ significantly both in Young’s modulus (t-test; p=0.0031) and in ultimate stress (p=0.00007). (\u003cstrong\u003eF-H\u003c/strong\u003e) Exemplary force-displacement curve (\u003cstrong\u003eF\u003c/strong\u003e), force plotted against actuator displacement or against the displacement assessed by landmark position (\u003cstrong\u003eG\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eH\u003c/strong\u003e) obtained during the experiment. During the last stage of the experiment (marked by red line segments) the grip displacement resulted mainly in sample slippage from the tags and virtually no hypocotyl strain. Three red line segments in F mark the curve points to which the measurements shown in G and three hypocotyl images in H correspond. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 0.28% for the first pair of images, and 0.36% for the second. Because of substantial slippage of hypocotyl from the stickers, in the region marked by black asterisks, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e. 5.19% and 4.17%, respectively. (\u003cstrong\u003eI-J\u003c/strong\u003e) Exemplary results of creep experiment using the basic setup. Displacement rates of landmarks (blue) or actuator grips (red) plotted over time (\u003cstrong\u003eI\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eJ\u003c/strong\u003e) are shown. Displacement rates were computed for 300 s time intervals, based on landmark positions (marked by white arrows in images) or actuator position recorded in .csv file.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/2192bd12289ac8ef2095613d.png"},{"id":73843960,"identity":"bd45f5c1-1e0a-4db8-964e-d8cf409ff59d","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":265938,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOnion epidermal peel deformation in extensometer experiments can be accurately measured using cell junctions. \u003c/strong\u003e(\u003cstrong\u003eA-B\u003c/strong\u003e) Longitudinally stretched cell in a relaxed state (\u003cstrong\u003eA\u003c/strong\u003e) and under 10 % strain (\u003cstrong\u003eB\u003c/strong\u003e). Yellow line highlights cell junctions where distances were measured from. (\u003cstrong\u003eC\u003c/strong\u003e) Corresponding force-displacement curve for longitudinally stretched sample. (\u003cstrong\u003eD-E\u003c/strong\u003e) Transversely stretched cell in a relaxed state (\u003cstrong\u003eD\u003c/strong\u003e) and under 10 % strain (\u003cstrong\u003eE\u003c/strong\u003e). Yellow line highlights cell junctions where distances were measured from. (\u003cstrong\u003eF\u003c/strong\u003e) Corresponding force-displacement curve for transversely stretched sample. Scale bars: 20 µm.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/4388630cbd0a089874d1699f.png"},{"id":73843967,"identity":"640e96ea-70a1-430f-8944-004f03f00187","added_by":"auto","created_at":"2025-01-15 08:45:58","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":477159,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCellular deformation analysis on Arabidopsis leaf\u003c/strong\u003e. (\u003cstrong\u003eA\u003c/strong\u003e) Arabidopsis leaf sample attached to tags prior to stretching. Scale bar: 1 mm. (\u003cstrong\u003eB-C\u003c/strong\u003e) Confocal z-stack images of abaxial leaf cells before stretching (B) and at 9.5% strain or maximum deformation before rupture (C). Arrows indicate the stretching direction. (\u003cstrong\u003eD\u003c/strong\u003e) Heatmap of cell deformation of selected cells. Deformation crosses are calculated using MorphoGraphX, with white arms indicating extension and red arms indicating contraction, visualized at the cell centroids. Arrows indicate the stretching direction. B, C, and D share the same scale bar of 50 µm. (\u003cstrong\u003eE\u003c/strong\u003e) Boxplot showing longitudinal and transverse strain (%) of the selected cells in D. Longitudinal strain corresponds to the stretching direction, while transverse strain is perpendicular to it. The grey dashed line at 0% indicates no change in cell size.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/3952ee7ebef172f6727646dd.png"},{"id":73845634,"identity":"a246512c-cb1a-42cf-beb3-4322f26f1af5","added_by":"auto","created_at":"2025-01-15 09:01:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3966214,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/38b8d075-6cd8-411c-bf9f-cea035b803c2.pdf"},{"id":73843956,"identity":"cb10470d-608f-4c78-9af2-f1bf7d3b7936","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"zip","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":604879,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryData.zip","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/12e887ebabc54878ab5df5a9.zip"},{"id":73843987,"identity":"37e20567-c6f2-4f80-bbf6-c8980b68cac6","added_by":"auto","created_at":"2025-01-15 08:45:59","extension":"avi","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":48628136,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMovie1.avi","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/6e2f54fc85aed06d8a1b695b.avi"},{"id":73843959,"identity":"fff5d5c8-11e2-401d-89dd-dfe273ea8ad5","added_by":"auto","created_at":"2025-01-15 08:45:57","extension":"gif","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":1234891,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMovie2.gif","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/0e0f06ddb9c3b0a25f68984d.gif"},{"id":73843969,"identity":"defa85e8-8194-4441-ad83-730f8a344676","added_by":"auto","created_at":"2025-01-15 08:45:58","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":12619356,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-5828617/v1/648a2b098b5fe1446f302405.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Camelot: a Computer Automated Micro Extensometer with Low-cost Optical Tracking","fulltext":[{"header":"Background","content":"\u003cp\u003eIn plants, growth and morphogenesis depend on the interaction of genetic networks, cell signaling, and mechanical forces. Turgor pressure within cells stretches the cell wall elastically, and under the influence of wall modifiers such as expansins, this tension causes the wall to expand through creep (1, 2). Creep occurs in the presence of cell wall modifiers when tensile stress exceeds a specific yield threshold, as described in Lockhart's growth framework (3-5). According to this framework, growth depends on the product of extensibility factors and turgor pressure exceeding the yield point. While expansins promote creep without affecting wall elasticity (4, 6), other proteins like xyloglucan endotransglucosylase/hydrolases (XTHs) also contribute to wall extensibility (7). On the other hand, wall stiffening can limit growth, as seen in cytokinin-induced cessation of root elongation (8). In recent years, novel methods have been developed to measure mechanical forces in plant tissues with most observations relying on stretching tissues with an extensometer and applying localized compression to cells or specific regions using an indenter (9-11). Extensometers quantify the stiffness of materials and how they respond to mechanical forces, allowing to evaluate elastic and plastic behavior, stress tolerance and fracture, and structural behavior.\u003c/p\u003e\n\u003cp\u003eTo measure the mechanical behavior of plant tissues, extensometers record how samples respond to applied forces. These devices quantify properties such as elasticity, creep, and yield stress of soft tissues by stretching samples while monitoring force and displacement. Strain is calculated by dividing displacement by the initial length, and stress is calculated by dividing force by the cross-sectional area. The stress-strain relationship over short time scales indicates stiffness, while creep is determined by measuring strain under constant stress over longer periods. Yield stress represents the minimum force required to initiate creep. Factors such as water movement in living tissues or cell wall viscosity in isolated samples can affect these measurements, causing relaxation or reversible deformation. Precise control of force, displacement, and timing is essential for accurate quantification of these mechanical properties.\u003c/p\u003e\n\u003cp\u003eEarly extensometers often used weights to measure creep (12). While simple and low-cost, these systems lack precise control over sample deformation, making them less suitable for stiffness tests on very small samples like \u003cem\u003eArabidopsis\u003c/em\u003e hypocotyls. Modern micro-extensometers, designed for such samples, typically employ a computer-controlled actuator to displace the sample attached to a force sensor, providing precise force measurements (13-15). While these setups are capable of accurately tracking actuator displacements, they often cannot precisely measure the sample’s deformation due to issues such as minor slippage at attachment points or alignment shifts as the tissue stretches. These challenges are particularly significant for smaller samples, making accurate stiffness measurements challenging without optical feedback. One solution is to mark the sample with landmarks and track its deformation using a digital camera (15, 16). Another approach involves mounting the extensometer on a microscope with adequate resolution to use cells as deformation landmarks (17-20).\u003c/p\u003e\n\u003cp\u003eRecent extensometer setups for small biological samples often rely on specialized hardware, such as piezoelectric actuators or high-resolution linear stages, which can be prohibitively expensive for labs with limited funding or researchers exploring biomechanics on a smaller scale. For example, systems using SmarAct or Zaber actuators provide precise motion control but are typically priced beyond the reach of many academic labs. Fortunately, the decreasing costs of consumer-grade devices have made precise micro-actuators and micro-force sensors more accessible for these applications. However, software remains a significant hurdle. Many control libraries for specialized devices are proprietary and offer minimal functionality tailored to specific hardware. In addition, experimental setups frequently require separate software for each component, including the actuator, force sensor, and camera, which complicates system integration and operation.\u003c/p\u003e\n\u003cp\u003eWe present a Camelot system that overcomes these challenges by providing a low-cost micro-extensometer setup that is easy to assemble with minimal resources and technical expertise. The system is controlled by MorphoRobotX (15, 21-23) (www.MorphoRobotX.org), an integrated software environment for mechanical experimentation. MorphoRobotX seamlessly controls a wide range of actuators, force sensors, and cameras, and is able to utilize widely available components from consumer devices. An entire Camelot system, including an actuator, force sensor, control electronics, and camera, achieves precision in the range of approximately 5 µm. The open-source software is free to use and runs on a Linux desktop, with USB connectivity ensuring compatibility with modest hardware, including use with laptops. Its portability and suitability for high-resolution optical tracking under a microscope make Camelot an ideal tool for researchers in resource-limited settings or those pursuing exploratory biomechanics work.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSystem overview\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Camelot micro-extensometer system consists of three primary components: a force sensor with a sample attachment point, an actuator with a second attachment point to stretch the sample, and a camera to monitor deformation (\u003cstrong\u003eFig. 1A; Suppl. Fig. 1\u003c/strong\u003e). The force sensor, or load cell (\u003cstrong\u003eSuppl. Fig. 1C-D\u003c/strong\u003e), positioned on the linear motion stage (\u003cstrong\u003eFig. 1A; Suppl. Fig. 1K\u003c/strong\u003e), is a parallel beam sensor commonly used in digital weighing scales, optimized for single-axis force measurement with minimal sensitivity to off-axis forces. Similar sensors were utilized by Bidhendi et al. (2020), and are available in various ranges, with a maximum force of several kilograms down to 10 grams. The 10g and 100g models in our system cost approximately 10 GBP each. The 10g sensor offers an accuracy of approximately 10 \u0026mu;N, making it highly suitable for precise biomechanical measurements on small samples (\u003cstrong\u003eSuppl. Fig. 1C-D\u003c/strong\u003e). For calibration, the force sensor is configured vertically using a custom 3D-printed holder for precise alignment and stability during force calibration (\u003cstrong\u003eFig. 1B; Suppl. Fig. 1N, Q\u003c/strong\u003e). Phidgets, or \u0026quot;Physical Widgets\u0026quot; provide an accessible interface for hardware control, analogous to software widgets in a graphical user interface (24). Multiple Phidgets, including those for force sensor and actuator control, can be connected to a single Phidget Hub via USB (\u003cstrong\u003eSuppl. Fig. 1I\u003c/strong\u003e), facilitating computer integration. The sensors use a Phidgets Wheatstone Bridge to measure small resistance changes caused by deflection. With a DC input of 5\u0026ndash;10 V, they generate an output voltage of 2\u0026ndash;10 mV per input volt, directly proportional to the applied load. This low output voltage is subsequently amplified to a range suitable for an analog-to-digital converter (typically 0 to 5- or 10-volts DC). Consistent with Bidhendi et al. (2020), we use a Phidgets bridge amplifier\u003cstrong\u003eError! Bookmark not defined.\u003c/strong\u003e power the sensor and amplify the signal (\u003cstrong\u003eSuppl. Fig. 1H\u003c/strong\u003e). The system\u0026apos;s modular design, featuring a Wheatstone Bridge and compatibility with various load cells, including S-beam sensors from Futek (www.futek.com) (13, 19), allows seamless integration with diverse optical components, such as C-mount microscope cameras used in confocal setups. For these setups, the baseplate is securely mounted on the microscope stage, aligning the force sensor and sample with the optical path for simultaneous imaging and mechanical testing (\u003cstrong\u003eFig. 1C\u003c/strong\u003e). The baseplate accommodates a Petri dish for sample hydration (\u003cstrong\u003eFig. 1D\u003c/strong\u003e) and the setup enables confocal imaging to observe deformation at cellular resolution during mechanical testing (\u003cstrong\u003eFig. 1E\u0026ndash;F\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 1 (\u003c/strong\u003e\u0026rarr; \u003cstrong\u003enext page): Fully integrated experimental setup for simultaneous mechanical measurement and imaging under a confocal microscope.\u0026nbsp;\u003c/strong\u003e(\u003cstrong\u003eA\u003c/strong\u003e) Overview of the assembled system, including the linear motion stage, the force sensor connected to the Wheatstone Bridge Phidget, with both connected to the VINT Hub Phidget to convert to USB. Electronic components are enclosed in a custom 3D-printed housing for protection and organization. The system interfaces with a computer via USB for real-time data acquisition and control. (\u003cstrong\u003eB\u003c/strong\u003e) Vertical configuration of the force sensor for calibration. The inset highlights the force sensor mounted in a custom 3D-printed holder with precise alignment for mechanical measurements. This configuration allows accurate force calibration while maintaining stability during operation. (\u003cstrong\u003eC\u003c/strong\u003e) Integration with a confocal microscope, with the baseplate securely mounted on the microscope stage to align the force sensor and sample with the optical path, enabling simultaneous imaging and mechanical testing. (\u003cstrong\u003eD\u003c/strong\u003e) Close-up of the sample mounted on the force sensor under the confocal microscope objective, positioned in a Petri dish for hydration and optical compatibility. (\u003cstrong\u003eE\u003c/strong\u003e) Confocal imaging of the sample under green fluorescence, showing alignment within the optical path. (\u003cstrong\u003eF\u003c/strong\u003e) Magnified view of the same sample under green fluorescence, illustrating finer details and secure alignment between the force sensor and the Wheatstone Bridge Phidget.\u003c/p\u003e\n\u003cp\u003eThe linear actuator in our system uses a stepper motor that drives a screw mechanism that moves a stage along linear rail (\u003cstrong\u003eSuppl. Fig. 1A, B\u003c/strong\u003e). Commonly used for precise movements in applications like CNC (Computer Numerical Control) machine control, these actuators are readily available in various sizes. Our setup features a compact actuator with a 1mm pitch screw, enabling 1mm of movement per full motor revolution. The stepper motor rotates in 1.8\u0026deg; increments, providing a movement precision of 5 \u0026mu;m per step, which meets the requirements of most experimental applications. For even finer control, the Phidgets stepper motor controller can subdivide these steps as needed (\u003cstrong\u003eSuppl. Fig. 1J\u003c/strong\u003e). The stepper motor follows the NEMA 11 standard, which specifies a 1.1-inch square faceplate, making it a compact and widely compatible choice. This standardization ensures easy assembly and interchangeability with components from different manufacturers. The uniform color coding of control wires further facilitates integration. The linear actuator selected for our setup has good build quality at a cost of approximately 50 GBP. It is durable, with no noticeable looseness in its mechanism, and has proven to be accurate and dependable for our experimental applications.\u003c/p\u003e\n\u003cp\u003eThe third component of the system is the camera, which integrates with the MorphoRobotX interface to capture deformation data. The software interface displays the menu for setup, calibration, and experiment execution, while a pop-up window shows force curves generated during stretching experiments, illustrating the force applied to the sample until rupture (\u003cstrong\u003eFig. 2A, B\u003c/strong\u003e). We use a compact USB digital microscope, with models providing a resolution of 2592 \u0026times; 1944 pixels available for approximately 100 GBP. At maximum magnification, the camera can visualize individual plant cells, but lower magnification is typically used to capture the full tissue section along with landmark dots, as demonstrated for onion epidermal cells and hypocotyl samples under tension (\u003cstrong\u003eFig. 2C, D\u003c/strong\u003e). The camera operates independently of the micro-extensometer setup, allowing the system to be conveniently used under a conventional microscope when required. Our software interfaces with the digital microscope using the standard Linux webcam driver and is compatible with a range of smaller digital microscope cameras. Through Linux libraries such as OpenCV (opencv.org) and Micro-Manager (micro-manager.org), support is provided for various microscope cameras (typically C-mount), which are used in experiments requiring higher resolution or specialized imaging. Additional software libraries provided by camera manufacturers, such as the IDS-Peak library, are installed for some experiments to enable compatibility with specific cameras that are not accessible through OpenCV or Micro-Manager. Since MorphoRobotX uses a plugin-based system for camera drivers (processes), it is possible to integrate any camera that can be accessed through Linux libraries.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 2: Overview of the MorphoRobotX interface and samples under tension.\u0026nbsp;\u003c/strong\u003e(\u003cstrong\u003eA\u003c/strong\u003e)\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eThe pop-up window (CFM Data Viewer) relative to the Extensometer process, showing the force curve generated during a stretching experiment, illustrating the force applied to the sample until rupture. (\u003cstrong\u003eB\u003c/strong\u003e) The MorphoRobotX interface menu displays all the necessary setup, calibration, and experiment execution processes. (\u003cstrong\u003eC\u003c/strong\u003e) Onion epidermal layer cells captured through the setup camera, showing the sample under tension without visible deformation. (\u003cstrong\u003eD\u003c/strong\u003e) Etiolated 3 days old Col-0 hypocotyl, attached to Tough-Tags with visible landmarks marked on the sample. The sample is shown at its ultimate stress point just before rupture, illustrating deformation under tension. Scale bars: 1 mm (C); 2 mm (D).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eBasic setup with digital microscope\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe basic Camelot setup was equipped with a compact digital microscope to track landmarks on the sample and the Young\u0026rsquo;s modulus and breaking stress of etiolated \u003cem\u003eArabidopsis\u003c/em\u003e hypocotyls was measured. The experiments were conducted on wild-type (Col-0) and \u003cem\u003exxt1 xxt2\u003c/em\u003e double mutant, which lacks xyloglucan in the cell walls (25). This allowed us to compare results obtained with Camelot to previously published data using alternative setups (25, 26). Prior to measurements, landmarks were applied to the surface of the hypocotyls using an India ink marker (Faber-Castell Pitt Artist Pen Brush, Black 199***). Before the experiment, three hypocotyls from each batch were imaged using a stereomicroscope (Leica M60) equipped with a digital camera (IC80 HD). These images were analyzed in ImageJ to measure the hypocotyl diameter, which was then used to calculate the cross-sectional surface area. Next, each hypocotyl was mounted between two transparent stickers (NIIMBOT Thermal Labels, Transparent Stickers, 14 \u0026times; 30 mm). One sticker secured the apical portion of the hypocotyl, including the cotyledons, while the other held the root and basal portion of the hypocotyl. After positioning either the cotyledon or root pole of the hypocotyl between the two halves of a folded sticker, each sticker was punched using an office puncher and mounted onto the pins connected to the load cell or actuator. Hypocotyl images captured after each stretching step (\u003cstrong\u003eSuppl. Movie 1\u003c/strong\u003e), along with corresponding force readings, were used to calculate Young\u0026rsquo;s modulus and ultimate stress for each sample (\u003cstrong\u003eFig. 3A-C\u003c/strong\u003e). For each hypocotyl, a nearly linear section of the force-displacement curve was identified (\u003cstrong\u003eFig. 3A\u003c/strong\u003e). This section spanned at least 50 steps, corresponding to a displacement of at least 0.25 mm, to minimize errors in strain assessment and allow for reliable calculations of material properties. Using ImageJ, we measured the distance between landmarks in images corresponding to the beginning and end of the selected linear portion of the force-displacement curve (\u003cstrong\u003eFig. 3B-C\u003c/strong\u003e). The relative distance increment (representing the actual sample strain) and the corresponding increase in stress (calculated as the applied force divided by the cross-sectional surface area of the hypocotyl) were used to compute Young\u0026rsquo;s modulus. For the same samples, the ultimate stress at the point of sample rupture was determined from the force-displacement curves (\u003cstrong\u003eFig. 3E\u003c/strong\u003e). The results of these analyses, performed with the basic Camelot setup, show consistent and statistically significant differences in Young\u0026rsquo;s modulus and ultimate stress between the etiolated hypocotyls of \u003cem\u003eArabidopsis\u003c/em\u003e Col-0 and the \u003cem\u003exxt1 xxt2\u003c/em\u003e mutant (\u003cstrong\u003eFig. 3D\u003c/strong\u003e) and are consistent with previous studies (25) where it was reported that the \u003cem\u003exxt1 xxt2\u003c/em\u003e mutant exhibits altered mechanical properties in its cell walls, including reduced tensile strength and stiffness.\u003c/p\u003e\n\u003cp\u003eClose examination of hypocotyl images captured during the measurements enabled us to distinguish between actual sample stretch and sample slippage from the grips (stickers), allowing for an accurate assessment of sample strain. This detailed imaging also facilitated a critical interpretation of the force-displacement curves. For instance, the curve shown in \u003cstrong\u003eFig. 3F\u0026nbsp;\u003c/strong\u003esuggests sample relaxation toward the end of the experiment. However, inspection of the images reveals that the observed decrease in force was primarily due to significant slippage of the hypocotyl from the stickers (\u003cstrong\u003eFig. 3F-H\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003eUsing etiolated hypocotyls of wild-type \u003cem\u003eArabidopsis\u003c/em\u003e, we conducted also a creep experiment to evaluate the time-dependent deformation of the samples (\u003cstrong\u003eFig. 3I-J\u003c/strong\u003e). As anticipated, the rate of sample creep, assessed based on the positions of landmarks, decreased over time (blue curve in \u003cstrong\u003eFig. 3I\u003c/strong\u003e). However, it is important to note that the rate of grip displacement during the experiment was higher and increased rather than decreased in the later stages. This behavior was attributed to significant sample slippage from the grips (red curve in \u003cstrong\u003eFig. 3I\u003c/strong\u003e). Our results demonstrate that basic Camelot set up is sufficient to produce data showing mechanical differences between two genotypes using simple pen dots as landmarks to measure displacement.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3 (\u003c/strong\u003e\u0026rarr;\u003cstrong\u003e\u0026nbsp;next page): Mechanical properties and deformation analysis of etiolated Arabidopsis hypocotyls under tension and creep experiments. (A-C)\u0026nbsp;\u003c/strong\u003eExemplary force-displacement curve (\u003cstrong\u003eA\u003c/strong\u003e), force plotted against actuator displacement or against the displacement assessed by landmark position (\u003cstrong\u003eB\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eC\u003c/strong\u003e) obtained during the experiment, which terminated by hypocotyl breakage. Three red line segments in (A) mark the curve points to which the measurements shown in (B) and the first three hypocotyl images in (C) correspond, the last image in C was obtained immediately after the hypocotyl breakage. The force increase between the first two segments and the strain computed based on the first two images were used to compute Young\u0026rsquo;s modulus. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 2.09% for the first pair of images, and 0.88% for the second. Because of some slippage of hypocotyl from the tags, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e., 5.90% and 4.57%, respectively. Young\u0026rsquo;s modulus (\u003cstrong\u003eD\u003c/strong\u003e) and ultimate stress at breakage (\u003cstrong\u003eE\u003c/strong\u003e) were estimated for Col-0 and \u003cem\u003exxt1 xxt2\u003c/em\u003e etiolated hypocotyls. Red lines within the boxes represent median; boxes delimit the first and third quantiles; whiskers extend from the box ends to adjacent values in the data as long as the most extreme values are within 1.5x interquartile range from the box end. Dots represent individual measurements. Hypocotyls of Col-0 (n=10) and \u003cem\u003exxt1 xxt2\u003c/em\u003e (n=8 for modulus; n=7 for ultimate stress) differ significantly both in Young\u0026rsquo;s modulus (t-test; p=0.0031) and in ultimate stress (p=0.00007). (\u003cstrong\u003eF-H\u003c/strong\u003e) Exemplary force-displacement curve (\u003cstrong\u003eF\u003c/strong\u003e), force plotted against actuator displacement or against the displacement assessed by landmark position (\u003cstrong\u003eG\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eH\u003c/strong\u003e) obtained during the experiment. During the last stage of the experiment (marked by red line segments) the grip displacement resulted mainly in sample slippage from the tags and virtually no hypocotyl strain. Three red line segments in F mark the curve points to which the measurements shown in G and three hypocotyl images in H correspond. Hypocotyl strain assessed based on the distance increase between landmarks marked by white arrows is 0.28% for the first pair of images, and 0.36% for the second. Because of substantial slippage of hypocotyl from the stickers, in the region marked by black asterisks, the corresponding strain computed based on the distance between the stickers (marked by black arrows) is much higher, i.e. 5.19% and 4.17%, respectively. (\u003cstrong\u003eI-J\u003c/strong\u003e) Exemplary results of creep experiment using the basic setup. Displacement rates of landmarks (blue) or actuator grips (red) plotted over time (\u003cstrong\u003eI\u003c/strong\u003e) and corresponding hypocotyl images (\u003cstrong\u003eJ\u003c/strong\u003e) are shown. Displacement rates were computed for 300 s time intervals, based on landmark positions (marked by white arrows in images) or actuator position recorded in .csv file.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSetup using C-mount\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003emicroscope camera\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA more accurate measure of deformation can be obtained by analyzing the cells or cell junctions as landmarks, using an inverted light or florescence microscope with a C-mount camera. For this setup, we placed Camelot on an inverted microscope (Axiovert 35M, Zeiss, Germany) with a C-mount camera (U3-3280SE, IDS, UK) to provide optical tracking. The IDS camera is just one example of a CCD camera that can be controlled by MorphoRobotX, synchronizing image capture with each step in the stepper motor. We stretched onion epidermal peels in both longitudinal and transverse directions (\u003cstrong\u003eFig. 4\u003c/strong\u003e) to test if similar results could be obtained to previously published data (15). Onion epidermal peels 4 mm wide, were prepared as described in Majda\u003cem\u003e\u0026nbsp;et al\u003c/em\u003e., (2022). Longitudinally stretched samples were mounted so that the direction of stretch was axial along the tissue and transversely stretched samples were mounted so that the direction of stretch was circumferential. Distance between cell junctions was measured in ImageJ to accurately determine strain.\u003c/p\u003e\n\u003cp\u003eLongitudinally stretched tissues reached a stress of 1.19 MPa at 10.6 % strain and withstood a maximum force of around 430000 \u0026micro;N before breakage. Transversely stretched tissues reached a stress of 2.08 MPa at 19.0 % strain and withstood a maximum force of around 300000 \u0026micro;N before breakage. At 10 % strain, longitudinally and transversely stretched samples had Young\u0026rsquo;s moduli of 11.23 MPa and 6.20 MPa, suggesting that the tissue is 1.94 times more stiff longitudinally than transversely, which is comparable with previous results (15). Strain was measured between two landmarks on the cells, instead of the position of the actuator, in the elastic region of the force/displacement curve. For the longitudinally stretched tissue, the distance in cell junctions increased from 147 \u0026micro;m to 175 \u0026micro;m, giving a strain of 19.0 %, whereas the actuator had moved from 730 mm to 1920 mm, giving an inaccurate strain of 95.5 %. For the transversely stretched tissue, the distance in cell junctions increased from 318.9 \u0026micro;m to 352.8 \u0026micro;m, giving a strain of 10.6 %, whereas the actuator had moved from 530 mm to 1110 mm, giving a strain of 163 %, more than an order of magnitude higher than distance measured from cell junctions. This suggests that displacement measurements without optical tracking can be highly inaccurate.\u003c/p\u003e\n\u003cp\u003eWe also found that the resolution and magnification are sufficient to capture mechanical failure at the cellular resolution. We could see that when a sample fails, the tissue separation occurred within a cell and propagated across the tissue. Thus, Camelot coupled with a top-mounted CCD can capture extensometer experiments with cellular resolution for accurate optical tracking.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 4. Onion epidermal peel deformation in extensometer experiments can be accurately measured using cell junctions.\u0026nbsp;\u003c/strong\u003e(\u003cstrong\u003eA-B\u003c/strong\u003e) Longitudinally stretched cell in a relaxed state (\u003cstrong\u003eA\u003c/strong\u003e) and under 10 % strain (\u003cstrong\u003eB\u003c/strong\u003e). Yellow line highlights cell junctions where distances were measured from. (\u003cstrong\u003eC\u003c/strong\u003e) Corresponding force-displacement curve for longitudinally stretched sample. (\u003cstrong\u003eD-E\u003c/strong\u003e) Transversely stretched cell in a relaxed state (\u003cstrong\u003eD\u003c/strong\u003e) and under 10 % strain (\u003cstrong\u003eE\u003c/strong\u003e). Yellow line highlights cell junctions where distances were measured from. (\u003cstrong\u003eF\u003c/strong\u003e) Corresponding force-displacement curve for transversely stretched sample. Scale bars: 20 \u0026micro;m.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eConfocal extensometer\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe used the confocal extensometer to analyze the deformation of epidermal cells from \u003cem\u003eArabidopsis\u003c/em\u003e leaf during stretching experiments. To facilitate tracking of the cell outlines, the plasma membrane marker line (\u003cem\u003epUBQ10::acyl-YFP\u003c/em\u003e) (27) was used. The samples were mounted onto Camelot\u0026rsquo;s extensometer arms using Tough-Tags and submerged in water within a small Petri dish to prevent desiccation.\u003c/p\u003e\n\u003cp\u003eThe setup was coupled with an upright Zeiss LSM 710 NLO confocal microscope, operated in single-photon mode. Confocal z-stack images were acquired at three stages: before stretching, during incremental deformation, and immediately prior to rupture (\u003cstrong\u003eFig. 5, Suppl. Fig. 2, Suppl. Movie 2\u003c/strong\u003e). These images were processed in MorphoGraphX (28) to compute the principal directions of deformation. Deformation was visualized at the cell centroids, with white lines indicating extension and red lines indicating contraction, with the lengths proportional to the amount.\u003c/p\u003e\n\u003cp\u003eDuring the stretching experiments, cells exhibited anisotropic deformation, characterized by elongation along the axis of applied force and contraction perpendicular to it. This behavior is consistent with the concept of Poisson\u0026apos;s ratio, which describes the ratio of transverse strain to axial strain in materials under stress. In plant cells, Poisson\u0026apos;s ratio typically ranges from 0.18 to 0.30 (29), reflecting the lateral contraction that accompanies axial stretching, although that is for the cell wall itself, and here a cellular tissue is being stretched.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 5\u003c/strong\u003e: \u003cstrong\u003eCellular deformation analysis on Arabidopsis leaf\u003c/strong\u003e.\u0026nbsp;(\u003cstrong\u003eA\u003c/strong\u003e) Arabidopsis leaf sample attached to tags prior to stretching. Scale bar: 1 mm. (\u003cstrong\u003eB-C\u003c/strong\u003e) Confocal z-stack images of abaxial leaf cells before stretching (B) and at 9.5% strain or maximum deformation before rupture (C). Arrows indicate the stretching direction. (\u003cstrong\u003eD\u003c/strong\u003e) Heatmap of cell deformation of selected cells. Deformation crosses are calculated using MorphoGraphX, with white arms indicating extension and red arms indicating contraction, visualized at the cell centroids. Arrows indicate the stretching direction. B, C, and D share the same scale bar of 50 \u0026micro;m. (\u003cstrong\u003eE\u003c/strong\u003e) Boxplot showing longitudinal and transverse strain (%) of the selected cells in D. Longitudinal strain corresponds to the stretching direction, while transverse strain is perpendicular to it. The grey dashed line at 0% indicates no change in cell size.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe Camelot system offers a simple and cost-effective solution for mechanical testing of small to medium-sized biological samples. It operates entirely on open-source software and is assembled from readily available consumer components. The cost and complexity of extensometer systems are largely influenced by the actuator choice. For instance, systems described by Schluck et al. (2013), Hofhuis et al. (2016) and Robinson et al. (2017) use SmarAct (www.smaract.com) piezo-based stick-slip positioners, which deliver nanometer resolution but have significant drawbacks. These high-quality positioners are costly, priced between 6,000–9,000 GBP depending on configuration, with long lead times and high sensitivity to dirt and shocks, making them complex to program and handle. A more affordable alternative involves high-precision screw-type linear stages from Thorlabs (14) or Zaber (30), costing around 1,350–2,000 GBP. While these actuators provide micrometer resolution, they remain expensive and may lack Linux driver support, as in the case of Thorlabs. Camelot uses a low-cost (50 GBP) screw drive actuator with an estimated 5 µm resolution sufficient for most sample testing. For example, achieving 5% deformation on a 5 mm sample would result in 50 steps. Although less precise than higher-end actuators, this resolution generally meets most experimental needs. Notably, relying solely on actuator position for tissue deformation measurement is impractical anyway due to sample slippage, rotation, and mounting tag flexibility, especially in smaller samples. Consequently, deformation needs to be measured through synchronized images, calculating distances between sample landmarks at each extension step. Thus, effective resolution depends on the accuracy of image-based landmark measurements rather than actuator precision.\u003c/p\u003e\n\u003cp\u003eTo demonstrate the utility of the device we performed experiments on living plant tissue in several configurations. In our most basic Camelot set up with a digital microscope, we were able to determine Young’s modulus and breaking stress of wild-type and \u003cem\u003exxt1 xxt2\u003c/em\u003e double mutant etiolated \u003cem\u003eArabidopsis\u003c/em\u003e hypocotyls. We tracked deformation using landmark points marked on the hypocotyl using a permanent marker from synchronized images recorded by the software. We found that Young’s modulus for wild-type was around five times higher than \u003cem\u003exxt1 xxt2\u003c/em\u003e, and that ultimate stress at breaking for wild-type was more than double that of \u003cem\u003exxt1 xxt2\u003c/em\u003e. This demonstrates that a complete Camelot system costing under 500 GBP can measure similar biomechanical differences to those previously reported (25). We also used the system to perform creep experiments that showed significant creep in the first 5 minutes, that tapered off over time. This demonstrates that a budget Camelot system can be used to perform a range of the most common extensometer experiments.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor labs that have access to microscopes with CCD cameras, we show that cellular level deformations can be tracked using mostly the same Camelot hardware. We used an IDS camera mounted to an inverted light microscope, but other cameras, microscope and fluorescence combinations can be also accommodated. Our data showed that onion epidermal peels are stiffer longitudinally than transversely, in line with previously published results (15).\u003c/p\u003e\n\u003cp\u003eCamelot can also be combined with confocal microscopy (18-20) by adapting the mounting board. This can be used to measure cell deformations and response under stress. \u003cem\u003eArabidopsis\u003c/em\u003e leaf was placed under a measured strain and the deformation of individual cells in a tissue was determined using MorphoGraphX to analyze their shape change. A combination of Camelot with confocal microscopy allows for precise segmentation and tracking of deformation at the individual cell level by using cell boundaries. However, the slower imaging speed of confocal microscopy can lead to partial sample relaxation between steps. Additionally, images must be synchronized manually with the Camelot system, as most commercial confocal setups currently lack open software integration to directly trigger image acquisition.\u003c/p\u003e\n\u003cp\u003eThe Camelot system provides a low-cost, accessible, open-source solution that can be built from widely available consumer components, adaptable for various experimental needs. Several potential improvements could enhance the system's capabilities. While the low-cost actuator’s resolution is sufficient for many biomechanical measurements, a higher-end device might be beneficial in specific scenarios, such as oscillatory loading/unloading (31), or precise force applications where actuator backlash could interfere. High-quality actuators, such as SmarAct models, also produce less vibration, which could be an issue for confocal applications. The MorphoRobotX software already supports SmarAct and Zaber stages, with options to integrate other types of actuators that have Linux drivers.\u003c/p\u003e\n\u003cp\u003eGiven the importance of accurate deformation tracking, another key improvement could involve automated landmark recognition, potentially through AI-based methods. This feature would allow users to select landmarks at the start of the experiment, with the software tracking the landmarks as the sample stretches, enabling automatic calculation of deformation for each step. Additionally, a movable camera stage could keep landmarks within the field of view, facilitating greater zoom and higher resolution. However, implementing these enhancements would add considerable complexity and cost to the system.\u003c/p\u003e\n\u003cp\u003eThis work demonstrates how an affordable and adaptable extensometer like Camelot can open new possibilities for biomechanical research, making complex measurements more accessible to a wider range of laboratories and encouraging deeper exploration of the forces that drive biological growth and development.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThe Camelot system is composed of modular 3D-printed components designed for mechanical testing of biological samples (\u003cstrong\u003eSuppl. Fig. 1K-Q\u003c/strong\u003e,\u003cstrong\u003e\u0026nbsp;Suppl. Fig. 3\u003c/strong\u003e). These components include the linear motion stage with a central hole for illumination, Petri plate positioning and actuator mounting (\u003cstrong\u003eSuppl. Fig. 3A, B, Suppl. Fig. 4B\u003c/strong\u003e), as well as a calibration stage with a central gap to securely hold the setup during calibration procedures (\u003cstrong\u003eSuppl. Fig. 3C, Suppl. Fig. 4E-F\u003c/strong\u003e). The arms of the micro-extensometer, equipped with pins for mounting samples using adhesive tape, ensure stable attachment to both the actuator and the sensor (\u003cstrong\u003eSuppl. Fig. 3D, E\u003c/strong\u003e). Additional structural components, such as the electronics box, protect the stepper controller and hub while providing sufficient ventilation and cable routing space (\u003cstrong\u003eSuppl. Fig. 3F-H, Suppl. Fig. 4C-D\u003c/strong\u003e). Collectively, these parts can be seamlessly assembled into a fully functional setup for calibration and micro-extensometer experiments (\u003cstrong\u003eFig. 1\u003c/strong\u003e), as shown in the detailed assembly steps in \u003cstrong\u003eFig. 6\u003c/strong\u003e,\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ewith the relative information for each component in \u003cstrong\u003eTable 1\u003c/strong\u003e. The Camelot setup can be configured for different experimental needs. For example, the basic configuration with a digital microscope enables straightforward mechanical measurements with high-resolution imaging (\u003cstrong\u003eSuppl. Fig. 5A, B\u003c/strong\u003e). Alternatively, the system can be mounted on an inverted microscope for cellular resolution (\u003cstrong\u003eSuppl. Fig. 5C-E\u003c/strong\u003e). Each setup is optimized for its specific purpose, whether focusing on external deformation measurements or high-resolution observations of tissue and cellular behavior. Assembly of the system begins with connecting the Wheatstone Bridge, sensor, and actuator to the Phidgets Hub and ensuring proper data flow to the computer (\u003cstrong\u003eFig. 6A-G\u003c/strong\u003e). The modular design allows mounting onto either a 3D-printed Camelot baseplate or a DIY plastic base created by drilling a plastic sheet to accommodate the setup (\u003cstrong\u003eSuppl. Fig. 5\u003c/strong\u003e). Additionally, detailed 3D-printing parameters are provided in \u003cstrong\u003eTable 2\u003c/strong\u003e, with .stl files available for download in \u003cstrong\u003eSuppl. Data 1\u003c/strong\u003e, making the system accessible and reproducible. These files can be easily and inexpensively uploaded to online manufacturing services, allowing users to have the components professionally fabricated with minimal effort.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 6: Step-by-step assembly guide for integrating the components into a functional system.\u003c/strong\u003e (\u003cstrong\u003eA\u003c/strong\u003e) Connect one end of the VINT cable to the Wheatstone Bridge Phidget (Phidgets DAQ1500) and the other end to Port 1 of the VINT Hub Phidget (Phidgets HUB0001). Ensure the cable is securely clicked into place. (\u003cstrong\u003eB\u003c/strong\u003e) Close-up of the VINT cable connection to the Wheatstone Bridge module, which transmits analog signals from the force sensor. (\u003cstrong\u003eC\u003c/strong\u003e) Plug the VINT cable from the Wheatstone Bridge into the VINT Hub Phidget (Port 1), allowing communication between the sensors and the computer. (\u003cstrong\u003eD\u003c/strong\u003e) \u0026nbsp;Connect a second VINT cable tointo another port on the VINT Hub Phidget for the stepper motor. (\u003cstrong\u003eE\u003c/strong\u003e) Attach the USB cable to the USB output of the VINT Hub Phidget and connect the other end to the computer for data acquisition and control. (\u003cstrong\u003eF\u003c/strong\u003e) Connect the Wheatstone Bridge Phidget to the VINT Hub Phidget and (\u003cstrong\u003eG-H\u003c/strong\u003e) to the wiring harness of the force sensor using the screw terminals. Match the wiring colors to the terminal labels for proper signal and power alignment (e.g., red for power, black for ground, green and white for signal). (\u003cstrong\u003eG\u003c/strong\u003e) Close-up of the Wheatstone Bridge Phidget\u0026rsquo;s terminals with all wires securely fastened using a small flathead screwdriver. Check if wires are tightly clamped for stable signal transmission. (\u003cstrong\u003eH\u003c/strong\u003e) Attach the force sensor (Phidgets 3133_0 Micro Load Cell) to the Wheatstone Bridge harness. Use a custom mount to position the force sensor correctly for force measurements. (\u003cstrong\u003eI\u003c/strong\u003e) Ensure the wiring harness for the force sensor is properly routed, avoiding sharp bends to prevent wire damage. (\u003cstrong\u003eJ\u003c/strong\u003e) Mount the force sensor on its designated holder or fixture to align it with the experimental setup. (\u003cstrong\u003eK\u003c/strong\u003e) Plug the VINT cable from the VINT hub into the stepper motor Phidget. (\u003cstrong\u003eL\u003c/strong\u003e) Prepare the power and motor control wires by stripping the ends to expose the metal conductors for secure attachment. (\u003cstrong\u003eM\u003c/strong\u003e) Stepper motor Phidget (Phidgets STC1002_0). (\u003cstrong\u003eN\u003c/strong\u003e) Securely attach the stepper motor wires to the motor controller, ensuring the wires are inserted into the correct terminals (A+, A-, B+, B-) to match the motor coil configuration. (\u003cstrong\u003eO\u003c/strong\u003e) Plug the VINT cable from the VINT hub into the motor controller. (\u003cstrong\u003eP\u003c/strong\u003e) Connect the motor controller to the power supply ensuring polarity is correct (red for positive, black for ground). (\u003cstrong\u003eQ\u003c/strong\u003e) Mount the linear motion stage (THK KR20 Linear Stage) by aligning the mounting holes of the stage and securing the motor controller using screws. (\u003cstrong\u003eR\u003c/strong\u003e) Power supply, (Mean Well GST25A05-P1J) 12VDC, 2 amps. (\u003cstrong\u003eS\u003c/strong\u003e) Assemble all components onto the custom 3D-printed \u0026quot;Camelot\u0026quot; baseplate. Use screws to secure the VINT Hub, Wheatstone Bridge, motor controller, and linear motion stage to the baseplate. Check if all components are stable and properly aligned. Arrows in the figure illustrate the sequence of connections and the flow of data and power across the system. Scale bar: 30 mm.\u003c/p\u003e\n\u003cp\u003eThe linear motor stage of the Camelot system integrates with advanced imaging platforms, including confocal, two-photon, and epifluorescence microscopes, to enable simultaneous mechanical measurements and high-resolution imaging. As shown in \u003cstrong\u003eSuppl.\u003c/strong\u003e \u003cstrong\u003eFig. 6\u003c/strong\u003e, the force sensor and sample holder align within the optical path, ensuring positioning under the confocal objective lens (\u003cstrong\u003eSuppl. Fig. 6A-B\u003c/strong\u003e). The stability provided by the \u0026quot;Camelot\u0026quot; baseplate supports reliable imaging and mechanical testing without interference from sensor wiring (\u003cstrong\u003eSuppl. Fig. 6C-D\u003c/strong\u003e). The system demonstrates versatility in capturing fluorescence signals at different wavelengths, using green and blue laser illumination to produce clear, interference-free images of the sample during mechanical experiments (\u003cstrong\u003eSuppl. Fig. 6E\u0026ndash;H\u003c/strong\u003e). This capability allows detailed observation of sample behavior under mechanical stress. When used with an inverted microscope, the Camelot system maintains its adaptability. As shown in \u003cstrong\u003eSuppl.\u003c/strong\u003e \u003cstrong\u003eFig. 7\u003c/strong\u003e, the baseplate is securely mounted on adjustable brackets, aligning the force sensor and other components with the optical path (\u003cstrong\u003eSuppl. Fig. 7A\u0026ndash;C\u003c/strong\u003e). Samples positioned within a Petri dish are located for simultaneous imaging and force measurements, while the modular design ensures accessibility and alignment of all components (\u003cstrong\u003eSuppl. Fig. 7D\u0026ndash;H\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eControl software\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Camelot system is controlled by MorphoRobotX (www.MorphoRobotX.org) (\u003cstrong\u003eFig. 2\u003c/strong\u003e), which serves as the control software for the Cellular Force Microscope (22, 32), and various extensometer setups (15, 21, 23). The graphical user interface for MorphoRobotX is modeled after MorphoGraphX (28), and users are encouraged to familiarize themselves with MorphoGraphX to better understand its layout and functionality. As with MorphoGraphX, MorphoRobotX organizes tasks into processes, which manage key operations such as stage movement, sample stretching, calibration, and parameter settings. These processes also represent hardware components (drivers), including the camera, actuator, and force sensor, and come pre-configured with experimental defaults. Additional hardware elements (actuators, cameras, acquisition devices) can be added via a plug-in system that allows the incorporation of additional processes. Throughout each session, MorphoRobotX creates logs, recording data such as forces, stage positions, and camera images which are synchronized with extensometer steps as the experiment progresses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExperimental Workflow\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental workflow for the Camelot system covers the key steps required for conducting mechanical testing and imaging experiments. It begins with calibrating the system\u0026apos;s hardware to achieve reliable measurements, followed by preparing the samples with appropriate mounting and hydration methods. Finally, the samples are stretched using either manual or automated procedures, allowing for accurate force application and imaging. This workflow is adaptable to various experimental setups and research objectives, providing flexibility while maintaining consistency in data collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSystem calibration\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo achieve accurate force measurements with the load cell, the sensor\u0026rsquo;s gain must be calibrated to accurately convert voltage readings into force. We encourage users to do this periodically, and to verify the calibration before and after experiments to ensure the sensor is not damaged.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasure and calculate the weight of a known load\u003c/strong\u003e: Use an analytical balance to measure the weight of the chosen calibration object (\u003cem\u003ee.g.\u003c/em\u003e, a screw, nut, or bolt) multiple times to minimize variability. Calculate the average weight by summing all measurements and dividing by the number of measurements. Convert the weight into force using the formula \u0026nbsp;, where \u0026nbsp;, with 1 gram equivalent to 9806.65 \u0026micro;N. Record this theoretical force as your reference value.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVerify hardware defaults and initialize components\u003c/strong\u003e: Before proceeding, confirm that the defaults for the sensor, actuator, and camera are correctly configured under \u0026quot;Tools/MorphoRobotX/Experiment Defaults\u0026rdquo;. Begin by initializing the actuator through \u0026quot;Tools/MorphoRobotX/Actuator/Phidgets Positioner\u0026quot;. Then, initialize the sensor by double-clicking on \u0026quot;Tools/MorphoRobotX/Sensors/Phidgets Sensor\u0026quot; to confirm that MorphoRobotX can communicate effectively with the hardware. If successful, nothing will happen, but if not, an error box will pop up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrepare the sensor and set the offset\u003c/strong\u003e: Once the hardware is properly initialized, move Camelot and the load cell to a vertical position using the 3D-printed calibration stand or any stable L-bracket to securely support the load cell. Open \u0026ldquo;Tools/MorphoRobotX/Sensors/Set Offset\u0026rdquo; and run the Set Offset process with the sensor alone, ensuring no weight is on the load cell. This action zeroes the sensor, removing any residual force readings. Then navigate to \u0026ldquo;Tools/MorphoRobotX/Experiment/Monitor Force\u0026rdquo;, activate the Monitor Force process to display real-time force measurements and confirm that the displayed force values are around zero.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eA\u003cstrong\u003edd the weight and check the force\u003c/strong\u003e\u003c/strong\u003e: Place the known weight on the load cell. Use \u0026ldquo;\u003cstrong\u003eTools/MorphoRobotX/Experiment/Monitor Force\u003c/strong\u003e\u0026rdquo; to observe the force value measured by the sensor. Use the \u0026ldquo;\u003cstrong\u003eTools/MorphoRobotX/Sensors/Calibrate Force\u003c/strong\u003e\u0026rdquo; process with the previously calculated value for the reference weight in the \u0026quot;Target Force\u0026quot; parameter. This will calculate the correct sensor gain and write it to the \u0026quot;Sensor Gain\u0026quot; parameter of the force sensor process.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMitigate environmental noise\u003c/strong\u003e: If fluctuations are observed in the force readings during calibration or use, consider addressing potential environmental factors. Noise can result from temperature changes, vibrations, or electromagnetic interference. To minimize these effects, ground the experimental setup and, if necessary, place the load cell and related components inside an isolation box. Additionally, use a vibration isolation table with pneumatic supports, which helps dampen external mechanical vibrations. These measures stabilize the sensor\u0026apos;s performance and ensure the reliability of its readings.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eValidate the calibration and document\u003c/strong\u003e: After calibration, remove the weight from the load cell and return Camelot to a horizontal position. Use \u0026ldquo;Tools/MorphoRobotX/Experiment/Monitor Force\u0026rdquo; to check the force. Since the weight of the sensor will affect the force, rerun \u0026ldquo;Tools/MorphoRobotX/Sensors/Set Offset\u0026rdquo; to zero it in the horizontal position. \u0026nbsp;Document the final gain value (from the \u0026quot;Sensor Gain\u0026quot; parameter on the sensor process) for future reference. A large change in this value could indicate damage to the sensor. The sensor is now ready for precise force quantification in experimental applications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSample preparation\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSample preparation for experiments using the Camelot system involves preparing adhesive tags as mounting points for tissue samples, selecting or dissecting samples according to the experimental design, and attaching the tissue ends to the tags. Artificial landmarks can be added to the samples to track deformation during testing. Hydration is maintained throughout to minimize changes in tissue properties. The prepared samples are mounted on the Camelot setup and aligned appropriately for stretching, with attention to uniform tension and proper positioning.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrepare the adhesive tags\u003c/strong\u003e: Before starting the experiment, prepare adhesive tags such as Tough-Tags (Diversified Biotech, Cat. No. TTLC-1000) or NIIMBOT Thermal Transparent Stickers. Punch holes in the tags using a hole puncher, making sure the holes are appropriately sized and positioned for mounting on the Camelot setup pins. If needed, apply an adhesive scale bar directly onto the tags, especially for small samples. Alternatively, if the adhesive tape has a known dimension (e.g., the Tough-Tags width of 12.7 mm), this can serve as a built-in scale bar.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSelect or dissect the tissue\u003c/strong\u003e: Once the adhesive tags are prepared, select or dissect the tissue sample according to the experimental requirements. For small samples, such as \u003cem\u003eArabidopsis\u003c/em\u003e hypocotyls or epidermal peels, use the prepared adhesive tags for mounting. For larger or thicker samples, such as pine or elm hypocotyls, consider using stronger adhesion methods, such as gluing the sample ends into small rubber tubes that can be secured with clamps (33).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMount the tissue ends onto adhesive tags\u003c/strong\u003e: Attach the ends of the tissue sample to the prepared adhesive tags. Fold each tag in half over the tissue to ensure full adhesion and even distribution of tensile force. Press the tags firmly to prevent slippage during the experiment. Verify that the tissue is aligned centrally within the tags for consistent stretching.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eApply landmarks\u003c/strong\u003e: To track tissue deformation, put landmarks on the tissue using a very thin, soft, waterproof marker, such as a fine eyeliner or permanent marker. These landmarks will assist in measuring changes in length and distance during stretching. Make sure that the application of the markers does not damage or deform the tissue (\u003cstrong\u003eFig. 2C\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrevent dehydration\u003c/strong\u003e: To prevent dehydration-related changes in tissue properties, place the prepared sample in water temporarily while additional samples are being prepared. Alternatively, if the sample is to be stretched immediately, proceed with mounting and stretching promptly to minimize dehydration.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMount the sample on the Camelot setup\u003c/strong\u003e: Transfer the prepared sample to the Camelot setup. Depending on the preparation method, either float the sample on the water surface of a water-filled plate before mounting or directly mount it onto the pins if stretching immediately without additional hydration. Verify that the adhesive tags are positioned correctly for secure attachment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSecure the sample on the pins\u003c/strong\u003e: Use forceps to handle the sample and carefully position the adhesive tags onto the pins or bolts of the Camelot setup. Push the tags firmly down onto the pins to confirm they are securely mounted. If the sample is in a water-filled plate, confirm that it is fully submerged and stabilized for the stretching process.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAlign the sample for stretching\u003c/strong\u003e: Adjust the actuator of the Camelot setup using \u0026quot;Tools/MorphoRobotX/Actuators/Move Actuator\u0026quot; to align the sample properly. Check whether the tissue is straight to help spread the tension evenly. Verify that the adhesive tags are securely mounted on the pins and that the sample is free from twisting or bending. Once the alignment is complete, the sample is now ready to be stretched.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStretching\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe system can be operated either manually or automatically. Manual operation is often used to evaluate system behavior and determine key parameters, such as the required step size and the stabilization time between steps. Automatic operation enables precise stretching, allowing the system to record each step across the range of applied forces while synchronizing images captured by the camera or microscope.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eManual stretching\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCapture an initial image\u003c/strong\u003e: Capture an image of the sample in its relaxed state. Ensure that the sample is well-aligned, and the scale bar and any landmarks are visible in the image.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStretch the sample\u003c/strong\u003e: Stretch the sample incrementally by moving the actuator using \u0026quot;Tools/MorphoRobotX/Actuators/Move Actuator\u0026quot;. Enter the desired distance for each stretch in the \u0026quot;Move Measure\u0026quot; parameter. Monitor the resulting force after each stretch using \u0026quot;Tools/MorphoRobotX/Experiment/Monitor Force\u0026quot; for consistent application of tension.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAllow the force to stabilize\u003c/strong\u003e: After each actuator movement, allow the force to stabilize before further stretching.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCapture images at each stretching point\u003c/strong\u003e: If a camera is integrated, open the camera interface through \u0026quot;Tools/MorphoRobotX/Camera/OpenCV Camera\u0026quot;. Use the \u0026quot;Take Snapshot\u0026quot; button in the camera window to capture images at each stretching point, ensuring documentation of the sample\u0026apos;s deformation throughout the experiment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAutomated stretching\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eActivate the camera\u003c/strong\u003e: Open the camera interface by double-clicking the appropriate camera type in \u0026quot;Tools/MorphoRobotX/Camera\u0026quot; folder. Check whether the camera feed is active, and the sample is in focus to capture the sample\u0026apos;s deformation throughout the experiment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConfigure automated stretching\u003c/strong\u003e: Initiate the automated stretching process by opening \u0026quot;Tools/MorphoRobotX/Experiment/Extensometer\u0026quot;. Set the total distance to be covered during the experiment using the \u0026quot;Distance\u0026quot; parameter. Define the step size with the \u0026ldquo;Step Size\u0026rdquo; parameter. Adjust step sizes based on sample characteristics. Smaller step sizes yield more data but increase experiment duration, while larger step sizes may risk sample damage.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConfigure the wait time\u003c/strong\u003e: If required, adjust the \u0026quot;Wait Time\u0026quot; parameter to change the amount of time to wait for force stabilization between steps. If the system is being used with a confocal microscope or a camera that is not integrated with MorphoRobotX, set this time to -1 and the system will pop-up a window and wait for confirmation that the image has been captured before proceeding to the next step.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCreep experiments\u003c/strong\u003e: For creep experiments, specify the starting force threshold using the \u0026quot;Creep Threshold\u0026quot; parameter. The system will stretch the sample at a constant rate until the specified force is reached, then make steps periodically as required to maintain that force. For elasticity experiments the \u0026quot;Creep Threshold\u0026quot; to 0, which is the default.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStart the stretching experiment\u003c/strong\u003e: Begin the experiment by double-clicking \u0026quot;Tools/MorphoRobotX/Experiment/Extensometer\u0026quot;. Real-time force readings and a live camera feed will display, and snapshots of the stretching sample will be saved automatically to disk.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eReturn to the starting position\u003c/strong\u003e: Once the total distance set for the experiment is reached, the actuator will automatically return to its starting position, completing the stretching cycle.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCancel if necessary\u003c/strong\u003e: If it is required to interrupt the experiment to stop the stretching, press the \u0026quot;Stop\u0026quot; button in the upper right-hand side of the MorphoRobotX window. Force readings and snapshots of the stretching sample will be saved automatically to disk. Use \u0026quot;Tools/MorphoRobotX/Actuators/Move Actuator\u0026quot; to manually return the actuator to its starting position and reset the setup as needed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eData analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEach automated extensometer experiment produces three sets of files, an Extensometer \u003cem\u003e.csv\u003c/em\u003e file, a Snapshots folder with camera images for each step in the experiment, and an MRXlog \u003cem\u003e.\u003c/em\u003ecsv file containing raw data from the sensor and actuator. These are named with a date and time stamp of when the experiment started. The Extensometer file has columns Position (nm), Force (\u0026micro;N) and Time (\u0026micro;s) data for each step of the extensometer experiment. Each actuator step is associated with a snapshot and a corresponding force value. For manual stretching, data is manually collected from both the relaxed and stretched states. Landmarks from snapshots or confocal scans, such as cell junctions, are used to measure linear distance changes. Confocal data segmented using MorphoGraphX\u003cem\u003e\u0026nbsp;\u003c/em\u003e(MGX) can provide information on area or volume changes. A force curve can be generated by plotting actuator steps against force. To determine stress, two points within the elastic region of the force curve are selected, and their corresponding actuator steps are analyzed. Snapshots from these steps are used to measure landmark displacements, such as cell junctions or applied markers, which are then used to calculate strain.\u003c/p\u003e\n\u003cp\u003eMechanical properties are assessed by calculating stress and strain from force-displacement data recorded during the extensometer experiment. Stress ( ) is calculated by dividing the applied force ( ) by the sample\u0026rsquo;s cross-sectional area ( ). For cylindrical samples, such as hypocotyls, stems, or roots, the cross-sectional area is determined using the formula \u0026nbsp;, where \u0026nbsp; is the radius. The radius can either be calculated by measuring the diameter of the sample under tension with the integrated digital microscope camera and halving it or by preparing cross-sections and averaging the radius of samples of the same genotype. For non-cylindrical samples, such as leaves, sepals, or epidermal peels, cross-sectional areas require different approaches. Cross-sections can be obtained to calculate an average area for the specific sample type. Alternatively, for approximate calculations, the known or measured thickness of the sample can be combined with its width to estimate the cross-sectional area as \u0026nbsp;. Strain ( ), expressed as a percentage, represents the relative elongation of the sample and is calculated as \u0026nbsp;. Here, \u0026nbsp; is the change in length, determined as the difference between the stretched length just before rupture and the initial length under tension ( ) (34).\u003c/p\u003e\n\u003cp\u003eAnalysis typically focuses on the linear elastic region of the stress-strain curve, where deformation is proportional to the applied force, following Hooke\u0026rsquo;s Law ( ), with \u0026nbsp; as the elastic modulus (34). This part of the curve avoids plastic deformations, capturing reversible deformations where the sample returns to its original shape upon force removal. Strains are typically limited to below 10-20% so that they remain within the range that would normally be experienced by the plant cell wall. These can be much higher when measuring failure stress or plasticity. By isolating the linear elastic region, a single number for the elastic modulus can be calculated for each sample.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eParts list\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1: Components and costs for the Camelot setup.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA detailed breakdown of the parts required for the Camelot setup, excluding 3D-printed components. Costs are provided in GBP (\u0026pound;).\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"665\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePart\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMake\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eModel\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCost (GBP)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eLinear actuator with motor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eBefenybay\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e50mm NEMA11 T6x1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eCamera (2592x1944)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eCelestron\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e44308\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e97\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e10g load cell\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eDongguan Science \u0026amp; Tech\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e10g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e8+16\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e100g load cell\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e139_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eStepper motor controller (8A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003eSTC1002_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eWheatstone Bridge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003eDAQ1500_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eVINT Hub\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003eHUB0001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003ePower supply (12Vdc, 2A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e3025_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eMini-USB Cable (180cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e3018_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e10cm cable (x2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003ePhidgets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e3003_0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e2-axis manual stage\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eHyuduo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e40x40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e3D-printed components\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eGeneric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003eNuts, bolts, small hardware\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003eGeneric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5871%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 36.0211%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.2004%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.2406%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e438\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 84.8156%;\"\u003e\n \u003cp\u003e\u003csup\u003e1\u003c/sup\u003eOrdered from Alibaba, shipping (16 GBP) costs more than a sensor (10 GBP), best to order multiples.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e2\u003c/sup\u003eThis stage is optional but helps to position the sample precisely. Any suitable stage can be used, for example one recycled from an old light microscope.\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e3\u003c/sup\u003eA home-made plastic base can also be used as an alternative to 3D-printing.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2: 3D-printed components and costs for the Camelot setup.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA detailed breakdown of the 3D-printed components required for the Camelot setup (\u003cstrong\u003eSuppl. Data 1\u003c/strong\u003e). Costs are provided in GBP.\u003c/p\u003e\n\u003cdiv align=\"Left\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"652\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComponent\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMaterial\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFilament\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eInfill (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSupports\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRotation\u003c/strong\u003e\u003cbr\u003e\u003cstrong\u003e\u0026nbsp;\u003cspan style=\"text-align: left;color: rgb(77, 81, 86);background-color: rgb(255, 255, 255);font-size: 14px;font-family: Arial, sans-serif;\"\u003e(\u0026deg;)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFilament use (g)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrinting time (h)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCost (GBP)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eLinear motor stage\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePETG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black, matte white\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eBuild plate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e88.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eCalibration stand\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePETG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eBuild plate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e86.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eElectronics box\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePLA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eEverywhere, tree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e102\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eBox lid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePLA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eBuild plate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003eY: 180\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e121.2\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eActuator arm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePETG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eEverywhere, tree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003eY: 180\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eSensor arm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 77px;\"\u003e\n \u003cp\u003ePETG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eMatte black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eEverywhere, normal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 462px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e401.7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e14.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e8.96\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConceptualization: RSS, DK, MM. Methodology: NT, WW, RKB, RSS, DK, MM. Investigation: NT, WW, RKB, AM, AC, NA, RSS, DK, MM. Formal analysis: NT, RKB, AM, RSS, DK, MM. Writing: NT, RKB, RSS, DK, MM. Funding acquisition: NT, RSS, DK, MM. Supervision: RSS, DK, MM.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eAuthors thank the Cellular Imaging Facility (CIF) at the University of Lausanne for support with confocal microscopy.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eCosgrove DJ. Wall extensibility: its nature, measurement and relationship to plant cell growth. New Phytol. 1993;124(1):1-23.\u003c/li\u003e\n \u003cli\u003eBidhendi AJ, Geitmann A. Relating the mechanics of the primary plant cell wall to morphogenesis. Journal of experimental botany. 2016;67(2):449-61.\u003c/li\u003e\n \u003cli\u003eLockhart JA. An analysis of irreversible plant cell elongation. Journal of Theoretical Biology. 1965;8(2):264-75.\u003c/li\u003e\n \u003cli\u003eCosgrove DJ. Loosening of plant cell walls by expansins. Nature. 2000;407(6802):321-6.\u003c/li\u003e\n \u003cli\u003eSchopfer P. Biomechanics of plant growth. American journal of botany. 2006;93(10):1415-25.\u003c/li\u003e\n \u003cli\u003eCosgrove DJ. Enzymes and other agents that enhance cell wall extensibility. Annual review of plant biology. 1999;50(1):391-417.\u003c/li\u003e\n \u003cli\u003eCosgrove DJ, Jarvis MC. Comparative structure and biomechanics of plant primary and secondary cell walls. Frontiers in plant science. 2012;3:204.\u003c/li\u003e\n \u003cli\u003eLiu S, Strauss S, Adibi M, Mosca G, Yoshida S, Ioio RD, et al. Cytokinin promotes growth cessation in the Arabidopsis root. Current Biology. 2022;32(9):1974-85. e3.\u003c/li\u003e\n \u003cli\u003eBidhendi AJ, Geitmann A. Methods to quantify primary plant cell wall mechanics. Journal of Experimental Botany. 2019;70(14):3615-48.\u003c/li\u003e\n \u003cli\u003eAlonso Baez L, Bacete L. Cell wall dynamics: novel tools and research questions. Journal of Experimental Botany. 2023;74(21):6448-67.\u003c/li\u003e\n \u003cli\u003eTrinh DC, Alonso-Serra J, Asaoka M, Colin L, Cortes M, Malivert A, et al. How Mechanical Forces Shape Plant Organs. Curr Biol. 2021;31(3):R143-r59.\u003c/li\u003e\n \u003cli\u003eCleland R. Cell wall extension. Annual review of plant physiology. 1971;22(1):197-222.\u003c/li\u003e\n \u003cli\u003eHofhuis H, Moulton D, Lessinnes T, Routier-Kierzkowska AL, Bomphrey RJ, Mosca G, et al. Morphomechanical Innovation Drives Explosive Seed Dispersal. Cell. 2016;166(1):222-33.\u003c/li\u003e\n \u003cli\u003eBidhendi AJ, Zamil MS, Geitmann A. Assembly of a simple scalable device for micromechanical testing of plant tissues. Methods in Cell Biology. 160: Elsevier; 2020. p. 327-48.\u003c/li\u003e\n \u003cli\u003eMajda M, Trozzi N, Mosca G, Smith RS. How Cell Geometry and Cellular Patterning Influence Tissue Stiffness. Int J Mol Sci. 2022;23(10).\u003c/li\u003e\n \u003cli\u003eGeitmann A, Ortega JK. Mechanics and modeling of plant cell growth. Trends in plant science. 2009;14(9):467-78.\u003c/li\u003e\n \u003cli\u003eHarris AR, Bellis J, Khalilgharibi N, Wyatt T, Baum B, Kabla AJ, et al. Generating suspended cell monolayers for mechanobiological studies. Nature protocols. 2013;8(12):2516-30.\u003c/li\u003e\n \u003cli\u003eSchluck T, Nienhaus U, Aegerter-Wilmsen T, Aegerter CM. Mechanical Control of Organ Size in the Development of the Drosophila Wing Disc. PLoS ONE. 2013;8(10):e76171.\u003c/li\u003e\n \u003cli\u003eRobinson S, Huflejt M, Barbier De Reuille P, Braybrook SA, Schorderet M, Reinhardt D, et al. An Automated Confocal Micro-Extensometer Enables in Vivo Quantification of Mechanical Properties with Cellular Resolution. The Plant Cell. 2017;29(12):2959-73.\u003c/li\u003e\n \u003cli\u003eChen S, Burda I, Jani P, Pendrak B, Silberstein MN, Roeder AH. Fibrous Network Nature of Plant Cell Walls Enables Tunable Mechanics for Development. bioRxiv. 2024:2024.10. 09.617478.\u003c/li\u003e\n \u003cli\u003eMollier C, Skrzydeł J, Borowska-Wykręt D, Majda M, Bayle V, Battu V, et al. Spatial consistency of cell growth direction during organ morphogenesis requires CELLULOSE SYNTHASE INTERACTIVE1. Cell Reports. 2023;42(7):112689.\u003c/li\u003e\n \u003cli\u003eMajda M, Sapala A, Routier-Kierzkowska AL, Smith RS. Cellular Force Microscopy to Measure Mechanical Forces in Plant Cells. Methods Mol Biol. 2019;1992:215-30.\u003c/li\u003e\n \u003cli\u003eBaba AI, Lisica L, Atakhani A, Aryral B, Bogdziewiez L, Erguvan \u0026Ouml;, et al. Rhamnogalacturonan-II dimerization deficiency impairs the coordination between growth and adhesion maintenance in plants. bioRxiv. 2024:2024.11. 26.625362.\u003c/li\u003e\n \u003cli\u003eGreenberg S, Fitchett C, editors. Phidgets: easy development of physical interfaces through physical widgets. Proceedings of the 14th annual ACM symposium on User interface software and technology; 2001.\u003c/li\u003e\n \u003cli\u003eCavalier DM, Lerouxel O, Neumetzler L, Yamauchi K, Reinecke A, Freshour G, et al. Disrupting Two Arabidopsis thaliana Xylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component. The Plant Cell. 2008;20(6):1519-37.\u003c/li\u003e\n \u003cli\u003eSowinski EE, Westman BM, Redmond CR, Kong Y, Olek AT, Olek J, et al. Lack of xyloglucan in the cell walls of the Arabidopsis xxt1/xxt2 mutant results in specific increases in homogalacturonan and glucomannan. The Plant Journal. 2022;110(1):212-27.\u003c/li\u003e\n \u003cli\u003eWillis L, Refahi Y, Wightman R, Landrein B, Teles J, Huang KC, et al. Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche. Proceedings of the National Academy of Sciences. 2016;113(51):E8238-E46.\u003c/li\u003e\n \u003cli\u003eStrauss S, Runions A, Lane B, Eschweiler D, Bajpai N, Trozzi N, et al. Using positional information to provide context for biological image analysis with MorphoGraphX 2.0. eLife. 2022;11.\u003c/li\u003e\n \u003cli\u003eWei C, Lintilhac PM, Tanguay JJ. An insight into cell elasticity and load-bearing ability. Measurement and theory. Plant Physiology. 2001;126(3):1129-38.\u003c/li\u003e\n \u003cli\u003eBl\u0026ouml;sch R, Plaza-W\u0026uuml;thrich S, Barbier de Reuille P, Weichert A, Routier-Kierzkowska A-L, Cannarozzi G, et al. Panicle angle is an important factor in tef lodging tolerance. Frontiers in plant science. 2020;11:61.\u003c/li\u003e\n \u003cli\u003eHayot CM, Forouzesh E, Goel A, Avramova Z, Turner JA. Viscoelastic properties of cell walls of single living plant cells determined by dynamic nanoindentation. Journal of experimental botany. 2012;63(7):2525-40.\u003c/li\u003e\n \u003cli\u003eRoutier-Kierzkowska A-L, Weber A, Kochova P, Felekis D, Nelson BJ, Kuhlemeier C, et al. Cellular Force Microscopy for in Vivo Measurements of Plant Tissue Mechanics. Plant Physiology. 2012;158(4):1514-22.\u003c/li\u003e\n \u003cli\u003eSaxe F, Weichold S, Reinecke A, Lisec J, D\u0026ouml;ring A, Neumetzler L, et al. Age effects on hypocotyl mechanics. PLoS One. 2016;11(12):e0167808.\u003c/li\u003e\n \u003cli\u003eNiklas KJ. Plant biomechanics: an engineering approach to plant form and function: University of Chicago press; 1992.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Biology](https://bmcbiol.biomedcentral.com/)","snPcode":"12915","submissionUrl":"https://submission.springernature.com/new-submission/12915/3","title":"BMC Biology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5828617/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5828617/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Plant growth and morphogenesis is a mechanical process controlled by genetic and molecular networks. Measuring mechanical properties at various scales is necessary to understand how these processes interact. However, obtaining a device to perform the measurements on plant samples of choice poses technical challenges and is often limited by high cost and availability of specialized components, the adequacy of which needs to be verified. Developing software to control and integrate the different pieces of equipment can be a complex task.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e To overcome these challenges, we have developed a computer automated micro-extensometer combined with low-cost optical tracking (Camelot) that facilitates measurements of elasticity, creep, and yield stress. It consists of three primary components: a force sensor with a sample attachment point, an actuator with a second attachment point, and a camera. To monitor force, we use a parallel beam sensor, commonly used in digital weighing scales. To stretch the sample, we use a stepper motor with a screw mechanism moving a stage along linear rail. To monitor sample deformation, a compact digital microscope or a microscope camera are used. The system is controlled by MorphoRobotX, an integrated open-source software environment for mechanical experimentation. We first tested the basic Camelot setup, equipped with a digital microscope to track landmarks on the sample surface. We demonstrate that the system has sufficient precision to measure the stiffness in delicate plant samples, the etiolated hypocotyls of \u003cem\u003eArabidopsis\u003c/em\u003e, and were able to measure stiffness differences between wild type and a xyloglucan-deficient mutant. Next, we placed Camelot on an inverted microscope and used C-mount microscope camera to track displacement of cell junctions. We stretched onion epidermal peels in longitudinal and transverse directions and obtained results similar to those previously published. Finally, we used the setup coupled with an upright confocal microscope and measured anisotropic deformation of individual epidermal cells during stretching of an \u003cem\u003eArabidopsis\u003c/em\u003eleaf.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e The portability and suitability of Camelot for high-resolution optical tracking under a microscope make it an ideal tool for researchers in resource-limited settings or those pursuing exploratory biomechanics work.\u003c/p\u003e","manuscriptTitle":"Camelot: a Computer Automated Micro Extensometer with Low-cost Optical Tracking","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-15 08:45:52","doi":"10.21203/rs.3.rs-5828617/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-02-17T03:56:40+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-02-14T19:25:49+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-02-04T09:21:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-02-01T13:04:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"184187334791726422283310564413937723114","date":"2025-01-28T18:04:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"266713280981977653433511225516464401261","date":"2025-01-25T18:46:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"256484195693382468199923818916229956074","date":"2025-01-24T03:47:12+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-01-23T17:10:05+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-01-15T17:40:58+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-01-15T09:19:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Biology","date":"2025-01-14T16:01:56+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Biology](https://bmcbiol.biomedcentral.com/)","snPcode":"12915","submissionUrl":"https://submission.springernature.com/new-submission/12915/3","title":"BMC Biology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"13f907f0-6437-4016-9c3a-1069c432190e","owner":[],"postedDate":"January 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-04-15T09:08:08+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-15 08:45:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5828617","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5828617","identity":"rs-5828617","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}