Optimizing radicle-tip cutting for improved growth and lateral root formation in pistachio seedlings

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Pistachio plants face challenges because of the limited lateral roots within a taproot system and the poor survival rates if the primary root tip is severed during transplantation. This study investigated the effects of radicle-tip cutting (RC) on lateral root formation and growth of Pistacia vera L. ‘Ohadi’ seedlings. A factorial experiment with varying radicle lengths (L1-L5) and cutting site portions (CS1-CS5) was conducted. Control plants had an intact radicle tip. Following treatment, seedlings were transferred to 2 L pots filled with perlite, and nourished weekly with half-strength Hoagland's solution. After nine weeks, growth parameters and root characteristics were assessed. Results indicated that optimal radicle-tip cutting occurred at a radicle length of 2–3 cm (L3), with an ideal cutting distance of 3 mm from the radicle-tip (CS3). This treatment (L3CS3) led to improved growth (plant height, leaf area, shoot fresh weight (FW), root FW, shoot dry weight (DW), root DW) and root architecture (number of lateral roots (NLR), network depth (NWDP), network volume (NWVL), network convex area (NWCA) parameters, enhancing plant vitality. These findings offer valuable insights for nurserymen aiming to produce pistachio seedlings with robust lateral roots and higher post-transplantation survival rates. Growth parameters Lateral roots Pistacia vera L. Root architecture Transplanting Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1 Introduction The genus Pistacia belongs to the family Anacardiaceae, which has several species; among them Pistacia vera L. has commercially valuable nuts (Ferguson et al., 1980 ). This species has a typical taproot system but insufficient lateral roots (Orhan et al., 2007 ). The production of rootstocks with strong roots and high establishment power significantly increases the production of this economic crop (Vahdati et al., 2021 ). The root system of plants plays a decisive role under stress and non-stress conditions. Roots are the first plant organs affected by water and nutrient deficiencies and communicate with aerial parts via sending/receiving physical and chemical signals. Tree roots are classified in two ways: those thicker than 2 mm (coarse roots) and those thinner than 2 mm (fine roots) (McCormack et al., 2015 ). Thicker roots absorb water from greater soil depths while thinner roots absorb nutrients, carbon, and water. These two root types are identified based on different characteristics such as longevity and biomass, and lignin content (Sadat-Hosseini et al., 2019 ). The plant root system is a bridge between the soil and the aerial part of the plant, which acts as a sensor for identifying abiotic and biotic stresses and other signals transmitted from soils and aerial parts. It is not outlandish to state that the final growth and development of a plant is determined by the root architecture. It enables plants to adjust to changing environmental climate and survive in different ecological conditions (Nibau et al., 2008 ). Root architecture arrangement depends on the relationship between growth rate and branching frequency for diverse root types. Diversity among shoot and root systems in the plant kingdom reflects the plethora of functions required for plant survival in diverse habitats. Evolution, as a result of natural selection and genetic drift, and environmental adaptation along with human manipulation also alter shoot and root system development (Larue et al., 2022 ). A primary concern for pistachio is poor establishment after being transferred from the nursery to the field (Orhan et al., 2007 ). The pistachio tree is particularly vulnerable to transplantation due to the risk of drying out caused by damage to its main root tip. Consequently, these trees are predominantly cultivated in nurseries in pots or grown directly from seeds in the field. Production of high-quality nursery grown seedlings is imperative. More efforts to improve post transplantation survival rates and decrease recovery periods prior to resumption of normal growth are needed. Pistachio seedlings with fewer roots are often less hardy and have lower growth and survival rates after planting in orchards (Haase et al., 2021 ). However, transplanting often causes root damage and reduces the effective root area, which causes water stress and hinders nutrient uptake (Tyree, 2005 ). Rapid root growth after transplantation is essential for increasing survival rates (Burdett, 1987 ). Thus, seedling survival after planting depends on its ability to form new roots (Mobli and Baninasab, 2009 ). Seedling root systems can be manipulated to lessen the effects of transplantation shock by increasing root numbers. This developmental boost can be achieved by root pruning in the nursery to stimulate lateral root expansion (Broschat and Donselman, 2019 ). Lateral roots (LRs) are vital for stress tolerance and plant productivity. Understanding how hormones and genes interact during lateral root expansion is a significant present-day challenge. Previous studies have indicated that each step of root formation, from initiation of lateral root primordia to emergence from the mother root, is a process controlled and regulated by endogenous and exogenous signals (Torres-Martínez et al., 2019 ). The ratio of auxins to cytokinins, controls plant growth and, most importantly, regulates primary and lateral root initiation (Larue et al., 2022 ). It was reported that exogenous application of 0.5 mg L − 1 brassinolide ( BR) can promote shoot growth and lateral roots production in Malus hupehensis apple seedlings. Evidence exists supporting the involvement of several specific genes and pathways in BR-mediated lateral root development (Mao et al., 2017 ). The majority of pistachio orchards are in warm dry areas (Esmaeilpour et al., 2016 ). In Iran, most pistachio trees are budded on Pistacia vera L. seedlings (Afrousheh and Javanshah, 2020 ). Rootstock selection is a key decision made early in pistachio orchard establishment and can alter growth, flowering, and overall fruit yield (Moriana et al., 2018 ). The pistachio root system is representative of a phreatophyte plant. Phreatophytes are deep-rooted plants that obtain a sizable portion of the water that it needs from the phreatic zone (zone of saturation) or the capillary fringe above the phreatic zone. Phreatophytes have extensive root systems allowing them to penetrate the soil deeply, an adaptation for survival in arid climates with minimal soil moisture. However, this type of root is not advantageous in orchards irrigated by pressurized irrigation systems. Pistachios have an axial root system but often have insufficient lateral root numbers to benefit from watering by irrigation (Ferguson et al., 1980 ; Nwaogu, 2014 ). Therefore, plant survival after transplantation to the field is a serious in pistachio nurseries. For production of healthy nursery trees, a well-developed root system and satisfactory branching is a prerequisite for a high percentage of bud growth (Orhan et al., 2007 ). Active growth of dicot primary roots may indicate apical dominance, where lateral root growth is suppressed. Removal of this primary root-tip stimulates the rapid formation of lateral root primordia, usually absent within intact roots (Aloni et al., 2006 ). Thus, having found a method to stimulate lateral root formation and emergence, growers have proceeded to cut pistachio root tips using the radicle-tip cutting (RC) method (Orhan et al., 2007 ). In order to revolutionize the establishment of pistachio seedlings and underscore the significance of lateral root formation and efficient root structure, we conducted a pioneering study on the impact of radicle-tip cutting on growth and root architecture. Our research addresses the limited scientific resources in this area, hypothesizing that cutting the root tip shortly after radicle emergence and at the site of cell division enhances root branching, facilitating continued growth post-transplantation. By disseminating methods that promote sufficient lateral roots and improve post-transplantation survival rates, our research significantly advances horticultural practices for pistachio seedling orchards. 2 Materials and methods 2.1 Plant materials Half-sib (HS) seeds of Pistacia vera L. ‘Ohadi’ taken from a commercial orchard were used as plant materials for the experiment. This variety is one of the most common commercial pistachio cultivars in Iran. It exhibits moderate growth strength and a spread growth habit. It is considered a suitable cultivar for the majority of pistachio-growing regions in Iran. The experiment was conducted under greenhouse conditions at the Faculty of Agricultural Technology, University of Tehran, Tehran, Iran, during 2021–2022. The HS seeds were stratified at 4 ◦ C for 60 days. After stratification, the seeds were first soaked in water for 12 h and then treated with 0.01% Captan fungicide for 20 min (Esmaeilpour et al., 2016 ). The seeds were planted in 2 L plastic pots (20 cm diameter and 20 cm height) containing small-size perlite. 2.2 Experimental set-up The experiment was conducted as a factorial (including two factors) based on a completely randomized design (CRD) with 15 treatments combination and three replications (each containing 10 plants). The factors were: (1) the length of the radicle when its tip is being cut including 0.5-1 (L1), 1–2 (L2), 2–3 (L3), 3–4 (L4) and 4–5 cm (L5), and (2) length of cutting site from radicle tip (CS) including 1 (CS1), 3 (CS3) and 5 mm (CS5). Control plant radicle tips were uncut (Fig. 1 ). Simultaneously, with the application of treatments, weak and off-type seedlings were removed; so that only one seedling was kept in each pot. The greenhouse's temperature and relative humidity (day/night) ranged between 24/19 ◦ C and 51/75% RH, respectively. Seedlings were grown under greenhouse conditions in a hydroponic system using ½ Hoagland’s solution for fertigation. After twelve weeks of planting, the root characteristics of the seedlings and their growth parameters were measured. 2.3 Measurements 2.3.1. Root architecture. At the end of the experiment (around nine weeks after applying the treatment or 12 weeks after planting), the roots were gently removed of the pots and then separated from the crown. An RGB digital camera was used to take images of the roots. The images were processed using GiaRoots® software (Galkovskyi et al., 2012 ). The parameters obtained using image processing included the number of lateral roots (NLR), network depth (NWDP: number of pixels in the vertical direction from the upper-most network pixel to the lower-most network pixel), ellipse aspect ratio (ELAX: ratio of the minor to the major axis of best fitting ellipse), network length distribution (NWLD: fraction of network pixels found in the lower 2/3 of the network which is defined based on network depth), network convex area (NWCA: area of the convex hull that encompasses the image) and network volume (NWVL: sum of the local volume at each pixel of the network skeleton, as approximated by a tubular shape whose radius is estimated from the image). 2.3.2 Growth characteristics. The growth characteristics evaluated in this experiment were included leaf area, plant height, fresh weight (FW) and dry weight (DW) of the shoot and root. For measuring leaf area, all leaves of each plant were placed on the surface without overlapping and photographed. The images were processed using Digimizer (Sala and Nutrition, 2017 ). Using a ruler, plant height was measured in centimeters (cm) from the soil surface to the apical meristem. Plant fresh and dry weights (root and shoot) were measured using a digital scale (with an accuracy of 0.0001). The plants were dried at 70°C for 48 h to evaluate dry weight (Gijón et al., 2010 ). 2.3.3 Plant vitality. The plant vitality index was assessed by a visual scoring method between 1 (the most damaged plants) to 5 (the plants with fully green leaves) (Füzy et al., 2019 ). 2.4 Statistical analyses All data followed a normal distribution based on a normality test. Two-way analysis of variance was used, and mean comparisons were made using Duncan's multiple range test. All analyses were performed by R software (version 4.1.3) using the “ggplot2”, “report”, “sjPlot”, “flextable”, “tidyve rse”, “ggstatsplot”, “dplyr”, “MASS”, “car”, and “easyanova” packages. 3. Results 3.1 Root architecture Study of the root systems showed that the interaction effects on NLR were significant ( P < 0.01 ). Based on the results, different treatments showed varying responses in terms of NLR, NWDP and NWCA. Plants from which 3 mm of the radicle tip was removed (CS3) when the radicle length reached 2–3 cm (L3) had significantly higher numbers (n = 32) of lateral roots. By increasing seedling root lengths to L4 (3–4 cm) and L5 (4-5cm), lateral root numbers (NLR) decreased. No significant difference was found between L1CS1, L1CS5 and the uncut control. These displayed the lowest NLR (Fig. 2 ). The root network convex area. NWCA was lowest in L1CS1 and did not differ significantly from the control, L1CS3, and L1CS5 treatments. The greatest NWCA belonged to the L3CS3, which also had the highest number of lateral roots. NWCA ascended from L1 to L3 but, when the length of the radicle reached to L4 and L5 and the cutting was done, NWCA decreased (Fig. 3 ). Network depth. The impact of radicle-tip cutting on NWDP showed that the L3CS1 treatment had the highest NWDP and no significant difference existed between the control and this treatment. The L1CS5 treatment had the lowest NWDP (Fig. 4 ). Root network volume. NWVL was significantly influenced by radicle length and cut size × radicle length interaction ( P < 0.01 ). The L3CS3 treatment resulted in the highest NWVL. Radicle lengths of 0.5-1 cm were deemed unsuitable for cutting, as they led to a reduction in lateral root numbers. Control plants exhibited similar NWCA and NWVL to those cut at L1 length with no significant difference between them (Fig. 5 ). Network length distribution. Root architecture data indicated that NWLD was significantly affected by radicle length ( P < 0.01 ) and size of the cutting site ( P < 0.0 5), as shown in the root architecture data. Control plants displayed the highest NWLD, comparable to L3CS3 and showed no significant differences. Ellipse aspect ratio . ELAX was unaffected by the treatments, with only the interaction of radicle length × cut size proving significant ( P < 0.05 ). Control plants exhibited the highest NWLD. There were no significant differences in NWLD between L1 and L5 (Table 1 ). 3.2 Growth characteristics The results revealed significant impacts of the studied treatments ( P < 0.01 ) on the FW and DW of shoot and root. The lowest FW and DW for both shoot and root were observed in L5CS5 and L1CS5 treatments. Differences occurred in the height of P. vera seedlings across treatments, with the tallest plants (22.6 cm) achieved through the L3CS3 treatment. Control plants had an average height of 9.6 cm, surpassing the L1 treatments (L1CS1, L1CS3, L1CS5) and L5CS5 (Table 1 ). In addition, the L3CS3 treatment demonstrated significantly higher leaf area, FW and DW for both root and shoot compared to the other treated seedlings and control. This treatment proved to be the most effective in terms of growth parameters, including the induction of lateral roots and root architecture parameters. Table 1 Mean values for plant height, leaf area, ellipse axes ratio, and network length distribution in pistachio seedlings under radicle-tip cutting treatments Treatment Characteristics Radicle length (L) Cut size (CS) Plant height (cm) Leaf area (cm2) ELAX NWLD L1 CS1 7.5 jk 0.28 h 0.2 de 0.13 g CS3 8.83 j 0.65 gh 0.13 e 0.2 fg CS5 6 k 0.28 h 0.22 de 0.13 g L2 CS1 16.6 d-f 3.4 b 0.54 b 0.37 de-g CS3 21.3 ab 2.06 c-e 0.3 c-e 0.53 b-d CS5 13.33 gh 3.11 b 0.3 c-e 0.43 c-f L3 CS1 18.33 cd 3.11 b 0.324 c-e 0.54 b-d CS3 22.6 ab 4.71 a 0.284 c-e 0.7 ab CS5 14 f-h 2.46 b-e 0.33 b-e 0.65 bc L4 CS1 15 fg 1.55 e-g 0.37 b-d 0.53 b-d CS3 20 bc 1.69 d-f 0.374 b-d 0.48 b-e CS5 9.66 ij 1.49 e-g 0.394 b-d 0.45 b-e L5 CS1 11.66 hi 1.98 de 0.36 b-d 0.34 d-g CS3 15.5 e-g 2.65 b-d 0.304 c-e 0.26 e-g CS5 5.33 k 0.86 h 0.355 b-d 0.194 fg Control - 9.66 ij 1.89 de 0.932 a 0.92 a L ** ** ns ** CS ** ** ns * L×CS ** ** * * ELAX: ellipse aspect ratio, NWLD: network length distribution. L: the length of the radicle when its tip is being cut including 0.5-1 (L1), 1–2 (L2), 2–3 (L3), 3–4 (L4) and 4–5 cm (L5); CS: the length of cutting site from radicle tip including 1 (CS1), 3 (CS3) and 5 mm (CS5). C: control (no cutting) *, **, ns: Significant differences at 5% and 1% probability levels and non-significantly different, respectively. 3.3 Plant vitality The L2, L3, and L4 treatments, along with the control group, displayed the highest level of vitality and a lower number of necrotic leaves. In contrast, the plants subjected to L5 and L1 treatments showed the lowest vitality, with a score of 1 (Fig. 8 ). 4 Discussion Root architecture plays a crucial role in the establishment and survival of plants in the field, emphasizing the reliance of plant establishment on root structure (Half, 2013 ). Root architecture is developed by combining the growth of existing roots and their tropism (for growth) with LR speed and position (Guyomarc’h et al., 2012 ). Well-developed roots in seedlings accelerate progress during acclimatization post-transplantation and reduce the time needed to reach the grafting stage(Vahdati et al., 2021 ). This study aims to optimize radicle cutting in pistachio trees to enhance seedling establishment during orchard initiation.. Pistachio root systems often lack lateral root production (Ferguson et al., 2005 ), increasing transplantation costs and reducing survival rates. Altering pistachio Root System Architecture (RSA) during the initial stages of seedling growth in the nursery would require less labor, lower costs, and improve survival in the field. Success of lateral root induction depends on external (changing environment, human manipulations) and internal (phytohormones) factors (Aloni et al., 2006 ; Larue et al., 2022 ). Pinching or halting radicle growth, which is applied to overcome apical dominance, allows the production of lateral roots (Kumar, 2021 ). Our results demonstrate that the success of root tip cutting depends on radicle length and cut site size. Optimal results were observed when the radicle length reached 2–3 cm, leading to improved growth, root architecture, and overall plant survival. However, any deviation away from this range, whether less or more, resulted in diminished growth indices. Cell division, primarily in the apical meristem, slows as it progresses to the elongation (EZ) and differentiation zones (DZ). Lateral roots originate from mature pericycle layer cells, a process potentially enhanced by removing the root tip, possibly through a cytokinin connection. Another potential mechanism, similar to what we observed in our findings, that could enhance the quantity of lateral roots is removal of the the root tip, possibly through its connection to cytokinin (Aloni et al., 2006 ). Cytokinins (CK) and indole-3-acetic acid (IAA) have antagonistic roles in the formation of lateral roots. Auxin promotes lateral root formation (Du and Scheres, 2018 ). Cytokinin concentration in the root tip determines the initiation of lateral root formation. A high concentration of CK in the root cap prevents formation of lateral roots in the root cap. Thus, lateral root initiation is located further from the root cap, where the CK concentration are lower (Aloni et al., 2006 ). Hence, root tip removal, especially in meristematic points, increases lateral root formation (Sorin et al., 2005 ). Our findings revealed that the maximum NLR was obtained by cutting 3 mm from the radicle tip. The density of meristematic cells is higher in this area. Our results parallel and support those of Orhan et al. ( 2007 ), who reported that radicle-tip cutting-treated seeds had significantly more lateral roots than controls. Manipulating root system architecture enhances water and nutrient efficiency, improving plant survival in challenging soils. Root system architecture (RSA) has many effects on growth and final product performance (de Dorlodot et al., 2007 ). Increased lateral roots boost total root area, mechanical strength, and soil exploration (Nibau et al., 2008 ). In our study, NWCA also increased with the increasing NLR. With an increase in root NWCA and NWDP, the plant has more access to water and food, a direct link to increased growth and performance (Nibau et al., 2008 ; Passot et al., 2016 ). In the other words, our results showed that by manipulating the root architecture and increasing the number of lateral roots and then the root volume, plant vitality and growth characteristics improved. The observed enhancement in growth parameters can be attributed to an increase in elemental uptake facilitated by the development of lateral roots. Architectural modifications of the root system in response to phosphate is important for plant nutrition. The main adaptive feature for phosphate access is the ability to detect different layers near the soil surface through changes in RSA (de la Riva et al., 2018 ). Phosphate deficiencies cause growth signals to shift focus from the PR to LRs. Growth of the PR inhibits LR elongation and suppresses initiation before emergence of a highly-branched, shallow root system. This evolutionary adaptation slows growth in deeper soils where nutrients are limited and redirects resources to root exploration of nutrient-rich topsoil and plant growth (Nibau et al., 2008 ). Lateral roots existing prior to tip excision were stimulated but slow to grow. In contrast, lateral roots developing after tip excision showed rapid, unchecked lateral growth, extending nearly to the length of taproots but no deeper (Hankin and Watson, 2020 ). This study may be useful for seedlings with lateral root deficiencies and low survival rates after transplantation. Only pericycle cells previously primed in the basal meristem go on to form lateral roots (Malamy and Benfey, 1997 ). A series of coordinated periclinal cell divisions lead to the formation of a lateral root primordium (De Smet et al., 2015 ). The study suggests that the distance between the cells increases as the radicle grows. The L3CS3 treatment disrupts the meristematic cell area, stimulating the radicle to become multi-branched. Therefore, with the age and increased distance of the radicle from the meristem zone, fewer lateral roots will be formed. In terms of cellular activity, cell division occurs in the meristem zone, and mature cells in the pericycle layer give rise to lateral roots. This study recommends the 3 mm distance for root tip excision to maximize meristem cells and increase lateral root numbers. As this work showed a significant increase in survival following transplantation, this study can serve as a foundation and starting point for investigations into other species with low post-transplantation survival rates. Therefore, mechanizing this technique can be considered for future studies aimed at reducing labor costs, increasing the chances of transplantation survival, and better establishment of pistachio plants in the orchard. 5 Conclusion The transplantation of pistachio trees often faces challenges due to damage to their main root tip. Consequently, alterations in the root structure and enhanced lateral root formation are likely to reduce seedling mortality and enhance the establishment and initial growth of the seedlings. This is the first study to demonstrate the most appropriate time and desirable cut size for inducing lateral roots in pistachio. Our results confirm that optimizing the radicle-tip cutting technique by focusing on the cutting time and length of the radicle-tip cutting site not only alters the root architecture to promote root branching, but also enhances the plant's vitality and initial growth. Our findings affirm that the success of root tip removal depends on two factors: the length of the radicle when its tip is being cut and the size of the cutting site. We found that root architecture, growth, and plant vitality were improved when the length of the radicle-tip cutting is 2–3 cm (L3). For optimal results, we recommend removing 3 mm from the radicle tip (as this area contains a higher concentration of meristematic cells) when its length is 2–3 cm. In essence, the L3CS3 treatment disrupts the meristematic region, promoting increased lateral root development. These findings offer valuable insights to pistachio nurseries, aiding in minimizing seedling losses during transportation and obtaining seedlings with robust root systems. Declarations Competing Interests The authors declare no competing interests. Author Contributions Conceptualization: M.R.R and S.S; methodology: M.R.R and S.S. and M.O.; software: M.O.; validation: M.R.R; S.S., M.M.A; writing original draft preparation: M.O; writing review and editing: M.O; M.R.R; S.S., S.L., M.M.A, R.S.M and K.V. visualization: M.O, S.S.; supervision: M.R.R; S.S. All authors have read and agreed to the published version of the manuscript. References Afrousheh, M., Javanshah, A., 2020. The effect of humic acid on the growth and physiological indices of pistachio seedling ( Pistacia vera ) under drought stress. J. Nuts 11, 1–12. https://doi.org/10.22034/jon.2020.1879490.1069 Aloni, R., Aloni, E., Langhans, M., Ullrich, C.I., 2006. 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Effect of exogenous Brassinolide (BR) application on the morphology, hormone status, and gene expression of developing lateral roots in Malus hupehensis. Plant Growth Regul. 82, 391–401. https://doi.org/10.1007/s10725-017-0264-5 McCormack, M.L., Dickie, I.A., Eissenstat, D.M., Fahey, T.J., Fernandez, C.W., Guo, D., Helmisaari, H.S., Hobbie, E.A., Iversen, C.M., Jackson, R.B., Leppälammi-Kujansuu, J., Norby, R.J., Phillips, R.P., Pregitzer, K.S., Pritchard, S.G., Rewald, B., Zadworny, M., 2015. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes. New Phytol. 207, 505–518. https://doi.org/10.1111/nph.13363 Mobli, M., Baninasab, B., 2009. Effect of indolebutyric acid on root regeneration and seedling survival after transplanting of three Pistacia species. J. Fruit Ornam. Plant Res. 17, 5–13. Moriana, A., Memmi, H., Centeno, A., Martín-Palomo, M.J., Corell, M., Torrecillas, A., Pérez-López, D., 2018. Influence of rootstock on pistachio (Pistacia vera L. cv Kerman) water relations. Agric. Water Manag. 202, 263–270. https://doi.org/10.1016/j.agwat.2017.12.026 Nibau, C., Gibbs, D.J., Coates, J.C., 2008. Branching out in new directions: The control of root architecture by lateral root formation. New Phytol. 179, 595–614. https://doi.org/10.1111/j.1469-8137.2008.02472.x Nwaogu, E.N., 2014. Soil fertility changes and their effects on ginger (Zingiber officinale Rosc.) yield response in an ultisol under different pigeon pea hedgerow alley management in South Eastern Nigeria. African J. Agric. Res. 9, 2158–2166. https://doi.org/10.5897/ajar2013.7291 Orhan, E., Esitken, A., Ercisli, S., Sahin, F., 2007. Effects of indole-3-butyric acid (IBA), bacteria and radicle tip- cutting on lateral root induction in Pistacia vera. J. Hortic. Sci. Biotechnol. 82, 2–4. https://doi.org/10.1080/14620316.2007.11512190 Passot, S., Gnacko, F., Moukouanga, D., Lucas, M., Guyomarc’h, S., Ortega, B.M., Atkinson, J.A., Belko, M.N., Bennett, M.J., Gantet, P., Wells, D.M., Guédon, Y., Vigouroux, Y., Verdeil, J.L., Muller, B., Laplaze, L., 2016. Characterization of pearl millet root architecture and anatomy reveals three types of lateral roots. Front. Plant Sci. 7, 1–11. https://doi.org/10.3389/fpls.2016.00829 Sadat-Hosseini, M., Vahdati, K., Boroomand, N., Mehdi-Arab, M., Asadi-Yekta, S., 2019. How walnut roots respond to drought stress: A morphological and anatomical study. South-Western J. Hortic. Biol. Environ. 10, 51–64. Sala, F., Nutrition, P., 2017. Studies regarding some morphometric and biomass allocation parameters in the urban habitat on plantago. Res. J. Agric. Sci. 49, 96–102. Sorin, C., Bussell, J.D., Camus, I., Ljung, K., Kowalczyk, M., Geiss, G., McKhann, H., Garcion, C., Vaucheret, H., Sandberg, G., Bellini, C., 2005. Auxin and Light Control of Adventitious Rooting in Arabidopsis Plant Cell-2005-Sorin-1343-59.pdf. Plant Cell 17, 1343–1359. https://doi.org/10.1105/tpc.105.031625.1 Torres-Martínez, H.H., Rodríguez-Alonso, G., Shishkova, S., Dubrovsky, J.G., 2019. Lateral root primordium morphogenesis in angiosperms. Front. Plant Sci. 10, 1–19. https://doi.org/10.3389/fpls.2019.00206 Tyree, M.T., 2005. Water relations of plants, Eco-Hydrology. https://doi.org/10.2307/3899732 Vahdati, K., Sarikhani, S., Arab, MM., Leslie, CA., Dandekar, AM., Aletà, N., Bielsa, B., Gradziel, TM., Montesinos, Á., Rubio-Cabetas, MJ., Sideli, GM., Serdar, Ü., Akyüz, B., Beccaro, GL., Donno, D., Rovira, M., Ferguson, L., Akbari, M., Sheikhi, A., Sestras, AF., Kafkas, S., Paizila, A., Roozban, MR., Kaur, A., Panta, S., Zhang, L., Sestras, RE., Mehlenbacher, S. 2021. Advances in rootstock breeding of nut trees: objectives and strategies. Plants 10 (11), 2234. https://doi.org/10.3390/plants10112234. 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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-4755928","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":335459559,"identity":"5cfadb3a-8a31-4a42-b9c0-848fe9e30525","order_by":0,"name":"Mozhdeh Osku","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Mozhdeh","middleName":"","lastName":"Osku","suffix":""},{"id":335459560,"identity":"bc07fce5-c3a2-453f-92d6-ad6fc2ea7a8c","order_by":1,"name":"Mahmoud Reza Roozban","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAtElEQVRIiWNgGAWjYLACxgYGBn4om4d4LZINzKRqMTjATKSbdGcfPvjw5w67POMb+QcYftQwyJg3ENBidi4t2UDyTHKx2Y1kBsaeYww8MgcIaTnDYyZh2MacuA2ohYG3gYFHgpDDwFoS2+oTN88A2vKXaC0H2w4nbpBIZmAm0ha2ZMPGM8cTZ5x5bHBY5pgEMVqYQSFWndjfnvjw4ZsaG3uCWlDAAQYG0jSMglEwCkbBKMABAJ9HOYTMr7gRAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-9982-8761","institution":"University of Tehran","correspondingAuthor":true,"prefix":"","firstName":"Mahmoud","middleName":"Reza","lastName":"Roozban","suffix":""},{"id":335459561,"identity":"7092d55b-f052-4741-a392-aca1cb9559a3","order_by":2,"name":"Saadat Sarikhani","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Saadat","middleName":"","lastName":"Sarikhani","suffix":""},{"id":335459562,"identity":"0e40c146-5785-419d-afff-a3aefb27451c","order_by":3,"name":"Shaneka Lawson","email":"","orcid":"","institution":"USDA Forest Service: US Department of Agriculture Forest Service","correspondingAuthor":false,"prefix":"","firstName":"Shaneka","middleName":"","lastName":"Lawson","suffix":""},{"id":335459563,"identity":"d60b06a2-f4ca-49d2-a19a-f4d66c1aaa9b","order_by":4,"name":"Mohammad Mehdi Arab","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"Mehdi","lastName":"Arab","suffix":""},{"id":335459564,"identity":"90785074-d3b0-47d4-a6f5-1758aea055c1","order_by":5,"name":"Kourosh Vahdati","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Kourosh","middleName":"","lastName":"Vahdati","suffix":""}],"badges":[],"createdAt":"2024-07-17 11:42:00","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4755928/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4755928/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":63575326,"identity":"04b7d7cf-db16-47f0-8c3d-01d2e069d81a","added_by":"auto","created_at":"2024-08-29 19:06:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":229938,"visible":true,"origin":"","legend":"\u003cp\u003eThe anatomy of a pistachio radicle. The cutting site, denoted as CS, encompasses both the basal and apical meristem. The schematic image is sourced from De Smet et al., 2015, Malamy and Benfey, 1997.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/a0d08d4417f2a1f43ea5fb44.png"},{"id":63575598,"identity":"3d7ce32e-6418-4e68-a933-9ee408402da2","added_by":"auto","created_at":"2024-08-29 19:14:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":34751,"visible":true,"origin":"","legend":"\u003cp\u003eThe number of lateral roots (NLR) (±SD) of pistachio (cv. Ohadi) subjected to radicle-tip cutting treatments. L refers to the radicle length during cutting, categorized as 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5). CS represents the cutting site’s distance from radicle tip including 1 (CS1), 3 (CS3) and 5 mm (CS5). The control (C) indicates no cutting.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/8abdebaa5d8175c4ac3b5f89.png"},{"id":63575322,"identity":"1377df4e-4d41-480d-bb35-7bf622b67785","added_by":"auto","created_at":"2024-08-29 19:06:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":24828,"visible":true,"origin":"","legend":"\u003cp\u003eThe root network convex area (NWCA) (±SD) in pistachio (cv. Ohadi) subjected to radicle-tip cutting treatments. L represents the radicle length during cutting, categorized as 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5). CS signifies the cutting site’s distance from the radicle tip, including 1 (CS1), 3 (CS3) and 5 mm (CS5). The control (C) indicates no cutting.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/1e5e37d69f0146fd3416d412.png"},{"id":63575599,"identity":"00887972-2647-4bb5-99e7-bd9d37a2a8c5","added_by":"auto","created_at":"2024-08-29 19:14:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":26765,"visible":true,"origin":"","legend":"\u003cp\u003eThe root network depth (NWDP) (±SD) in pistachio (cv. Ohadi) subjected to radicle-tip cutting treatments. L denotes the radicle length during cutting, categorized as 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5). CS indicates the cutting site’s distance from the radicle tip, including 1 (CS1), 3 (CS3) and 5 mm (CS5). The control (C) indicates no cutting.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/f8ff11e5d38cd0b6a102dd86.png"},{"id":63575324,"identity":"434d55c9-7255-42ca-b7e8-3695c796cc56","added_by":"auto","created_at":"2024-08-29 19:06:32","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24313,"visible":true,"origin":"","legend":"\u003cp\u003eThe root network volume (NWVL) (±SD) of pistachio (cv. Ohadi) under radicle-tip cutting treatments. L denotes the radicle length during cutting, categorized as 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5). CS indicates the cutting site’s distance from radicle tip, including 1 (CS1), 3 (CS3) and 5 mm (CS5). The control (C) indicates no cutting.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/18a190970f4da9b913238d6a.png"},{"id":63575600,"identity":"87174b7e-6ab3-4ee1-9da6-9ac1ae03c368","added_by":"auto","created_at":"2024-08-29 19:14:32","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":308147,"visible":true,"origin":"","legend":"\u003cp\u003eRoot architecture of pistachio (cv. Ohadi) under radicle-tip cutting treatments. A: L1CS3; B: L2CS3: C: L3CS3, D: L4CS3; E: L5CS3; F; Control. L: the length of the radicle when its tip is being cut including 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5); CS3: the length of cutting site from radicle tip is 3 mm.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/ce26709e1f49a6848fd33048.png"},{"id":63575327,"identity":"34e1f1e0-ac85-4de8-b4b8-4791ba6b4f1b","added_by":"auto","created_at":"2024-08-29 19:06:32","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":84494,"visible":true,"origin":"","legend":"\u003cp\u003eThe fresh (FW) and dry (DW) weight of pistachio seedling (cv. Ohadi) (±SD) under radicle-tip cutting treatments. L: the length of the radicle when its tip is being cut including 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5); CS: the length of cutting site from radicle tip including 1 (CS1), 3 (CS3) and 5 mm (CS5). C: control (no cutting)\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/cc7c3d8e46e9eadec721301d.png"},{"id":63575601,"identity":"c753bac4-9a2b-42d8-b7a7-0363e09322b5","added_by":"auto","created_at":"2024-08-29 19:14:32","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":319473,"visible":true,"origin":"","legend":"\u003cp\u003eThe vitality of pistachio (cv. Ohadi) seedling under radicle-tip cutting treatments. L: the length of the radicle when its tip is being cut including 0.5-1 (L1), 1-2 (L2), 2-3 (L3), 3-4 (L4) and 4-5 cm (L5), and C: Control\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/0c116b82c937c4352e6649e7.png"},{"id":77124454,"identity":"83c08df6-e13d-4184-b226-3ae554b32ff2","added_by":"auto","created_at":"2025-02-25 11:00:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1713006,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4755928/v1/42f0e0bf-09de-450c-8f4e-9aeb081e97d1.pdf"}],"financialInterests":"","formattedTitle":"Optimizing radicle-tip cutting for improved growth and lateral root formation in pistachio seedlings","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eThe genus \u003cem\u003ePistacia\u003c/em\u003e belongs to the family Anacardiaceae, which has several species; among them \u003cem\u003ePistacia vera\u003c/em\u003e L. has commercially valuable nuts (Ferguson et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1980\u003c/span\u003e). This species has a typical taproot system but insufficient lateral roots (Orhan et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). The production of rootstocks with strong roots and high establishment power significantly increases the production of this economic crop (Vahdati et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe root system of plants plays a decisive role under stress and non-stress conditions. Roots are the first plant organs affected by water and nutrient deficiencies and communicate with aerial parts via sending/receiving physical and chemical signals. Tree roots are classified in two ways: those thicker than 2 mm (coarse roots) and those thinner than 2 mm (fine roots) (McCormack et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Thicker roots absorb water from greater soil depths while thinner roots absorb nutrients, carbon, and water. These two root types are identified based on different characteristics such as longevity and biomass, and lignin content (Sadat-Hosseini et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe plant root system is a bridge between the soil and the aerial part of the plant, which acts as a sensor for identifying abiotic and biotic stresses and other signals transmitted from soils and aerial parts. It is not outlandish to state that the final growth and development of a plant is determined by the root architecture. It enables plants to adjust to changing environmental climate and survive in different ecological conditions (Nibau et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Root architecture arrangement depends on the relationship between growth rate and branching frequency for diverse root types. Diversity among shoot and root systems in the plant kingdom reflects the plethora of functions required for plant survival in diverse habitats. Evolution, as a result of natural selection and genetic drift, and environmental adaptation along with human manipulation also alter shoot and root system development (Larue et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA primary concern for pistachio is poor establishment after being transferred from the nursery to the field (Orhan et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). The pistachio tree is particularly vulnerable to transplantation due to the risk of drying out caused by damage to its main root tip. Consequently, these trees are predominantly cultivated in nurseries in pots or grown directly from seeds in the field. Production of high-quality nursery grown seedlings is imperative. More efforts to improve post transplantation survival rates and decrease recovery periods prior to resumption of normal growth are needed. Pistachio seedlings with fewer roots are often less hardy and have lower growth and survival rates after planting in orchards (Haase et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, transplanting often causes root damage and reduces the effective root area, which causes water stress and hinders nutrient uptake (Tyree, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Rapid root growth after transplantation is essential for increasing survival rates (Burdett, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1987\u003c/span\u003e). Thus, seedling survival after planting depends on its ability to form new roots (Mobli and Baninasab, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSeedling root systems can be manipulated to lessen the effects of transplantation shock by increasing root numbers. This developmental boost can be achieved by root pruning in the nursery to stimulate lateral root expansion (Broschat and Donselman, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Lateral roots (LRs) are vital for stress tolerance and plant productivity. Understanding how hormones and genes interact during lateral root expansion is a significant present-day challenge. Previous studies have indicated that each step of root formation, from initiation of lateral root primordia to emergence from the mother root, is a process controlled and regulated by endogenous and exogenous signals (Torres-Mart\u0026iacute;nez et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The ratio of auxins to cytokinins, controls plant growth and, most importantly, regulates primary and lateral root initiation (Larue et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). It was reported that exogenous application of 0.5 mg L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e brassinolide \u003cb\u003e(\u003c/b\u003eBR) can promote shoot growth and lateral roots production in \u003cem\u003eMalus hupehensis\u003c/em\u003e apple seedlings. Evidence exists supporting the involvement of several specific genes and pathways in BR-mediated lateral root development (Mao et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe majority of pistachio orchards are in warm dry areas (Esmaeilpour et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). In Iran, most pistachio trees are budded on \u003cem\u003ePistacia vera\u003c/em\u003e L. seedlings (Afrousheh and Javanshah, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Rootstock selection is a key decision made early in pistachio orchard establishment and can alter growth, flowering, and overall fruit yield (Moriana et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe pistachio root system is representative of a phreatophyte plant. Phreatophytes are deep-rooted plants that obtain a sizable portion of the water that it needs from the phreatic zone (zone of saturation) or the capillary fringe above the phreatic zone. Phreatophytes have extensive root systems allowing them to penetrate the soil deeply, an adaptation for survival in arid climates with minimal soil moisture. However, this type of root is not advantageous in orchards irrigated by pressurized irrigation systems. Pistachios have an axial root system but often have insufficient lateral root numbers to benefit from watering by irrigation (Ferguson et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1980\u003c/span\u003e; Nwaogu, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Therefore, plant survival after transplantation to the field is a serious in pistachio nurseries. For production of healthy nursery trees, a well-developed root system and satisfactory branching is a prerequisite for a high percentage of bud growth (Orhan et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eActive growth of dicot primary roots may indicate apical dominance, where lateral root growth is suppressed. Removal of this primary root-tip stimulates the rapid formation of lateral root primordia, usually absent within intact roots (Aloni et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Thus, having found a method to stimulate lateral root formation and emergence, growers have proceeded to cut pistachio root tips using the radicle-tip cutting (RC) method (Orhan et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn order to revolutionize the establishment of pistachio seedlings and underscore the significance of lateral root formation and efficient root structure, we conducted a pioneering study on the impact of radicle-tip cutting on growth and root architecture. Our research addresses the limited scientific resources in this area, hypothesizing that cutting the root tip shortly after radicle emergence and at the site of cell division enhances root branching, facilitating continued growth post-transplantation. By disseminating methods that promote sufficient lateral roots and improve post-transplantation survival rates, our research significantly advances horticultural practices for pistachio seedling orchards.\u003c/p\u003e"},{"header":"2 Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Plant materials\u003c/h2\u003e\n \u003cp\u003eHalf-sib (HS) seeds of \u003cem\u003ePistacia vera\u003c/em\u003e L. \u0026lsquo;Ohadi\u0026rsquo; taken from a commercial orchard were used as plant materials for the experiment. This variety is one of the most common commercial pistachio cultivars in Iran. It exhibits moderate growth strength and a spread growth habit. It is considered a suitable cultivar for the majority of pistachio-growing regions in Iran.\u003c/p\u003e\n \u003cp\u003eThe experiment was conducted under greenhouse conditions at the Faculty of Agricultural Technology, University of Tehran, Tehran, Iran, during 2021\u0026ndash;2022. The HS seeds were stratified at 4\u003csup\u003e◦\u003c/sup\u003eC for 60 days. After stratification, the seeds were first soaked in water for 12 h and then treated with 0.01% Captan fungicide for 20 min (Esmaeilpour et al., \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e). The seeds were planted in 2 L plastic pots (20 cm diameter and 20 cm height) containing small-size perlite.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Experimental set-up\u003c/h2\u003e\n \u003cp\u003eThe experiment was conducted as a factorial (including two factors) based on a completely randomized design (CRD) with 15 treatments combination and three replications (each containing 10 plants). The factors were: (1) the length of the radicle when its tip is being cut including 0.5-1 (L1), 1\u0026ndash;2 (L2), 2\u0026ndash;3 (L3), 3\u0026ndash;4 (L4) and 4\u0026ndash;5 cm (L5), and (2) length of cutting site from radicle tip (CS) including 1 (CS1), 3 (CS3) and 5 mm (CS5). Control plant radicle tips were uncut (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Simultaneously, with the application of treatments, weak and off-type seedlings were removed; so that only one seedling was kept in each pot. The greenhouse\u0026apos;s temperature and relative humidity (day/night) ranged between 24/19\u003csup\u003e◦\u003c/sup\u003eC and 51/75% RH, respectively. Seedlings were grown under greenhouse conditions in a hydroponic system using \u0026frac12; Hoagland\u0026rsquo;s solution for fertigation. After twelve weeks of planting, the root characteristics of the seedlings and their growth parameters were measured.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Measurements\u003c/h2\u003e\u003cspan\u003e\n \u003cp\u003e\u003cstrong\u003e2.3.1. Root architecture.\u003c/strong\u003e At the end of the experiment (around nine weeks after applying the treatment or 12 weeks after planting), the roots were gently removed of the pots and then separated from the crown. An RGB digital camera was used to take images of the roots. The images were processed using GiaRoots\u0026reg; software (Galkovskyi et al., \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). The parameters obtained using image processing included the number of lateral roots (NLR), network depth (NWDP: number of pixels in the vertical direction from the upper-most network pixel to the lower-most network pixel), ellipse aspect ratio (ELAX: ratio of the minor to the major axis of best fitting ellipse), network length distribution (NWLD: fraction of network pixels found in the lower 2/3 of the network which is defined based on network depth), network convex area (NWCA: area of the convex hull that encompasses the image) and network volume (NWVL: sum of the local volume at each pixel of the network skeleton, as approximated by a tubular shape whose radius is estimated from the image).\u003c/p\u003e\n \u003c/span\u003e \u003cspan\u003e\n \u003cp\u003e\u003cstrong\u003e2.3.2 Growth characteristics.\u003c/strong\u003e The growth characteristics evaluated in this experiment were included leaf area, plant height, fresh weight (FW) and dry weight (DW) of the shoot and root. For measuring leaf area, all leaves of each plant were placed on the surface without overlapping and photographed. The images were processed using Digimizer (Sala and Nutrition, \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). Using a ruler, plant height was measured in centimeters (cm) from the soil surface to the apical meristem. Plant fresh and dry weights (root and shoot) were measured using a digital scale (with an accuracy of 0.0001). The plants were dried at 70\u0026deg;C for 48 h to evaluate dry weight (Gij\u0026oacute;n et al., \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e\n \u003c/span\u003e \u003cspan\u003e\n \u003cp\u003e\u003cstrong\u003e2.3.3 Plant vitality.\u003c/strong\u003e The plant vitality index was assessed by a visual scoring method between 1 (the most damaged plants) to 5 (the plants with fully green leaves) (F\u0026uuml;zy et al., \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\n \u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Statistical analyses\u003c/h2\u003e\n \u003cp\u003eAll data followed a normal distribution based on a normality test. Two-way analysis of variance was used, and mean comparisons were made using Duncan\u0026apos;s multiple range test. All analyses were performed by R software (version 4.1.3) using the \u0026ldquo;ggplot2\u0026rdquo;, \u0026ldquo;report\u0026rdquo;, \u0026ldquo;sjPlot\u0026rdquo;, \u0026ldquo;flextable\u0026rdquo;, \u0026ldquo;tidyve rse\u0026rdquo;, \u0026ldquo;ggstatsplot\u0026rdquo;, \u0026ldquo;dplyr\u0026rdquo;, \u0026ldquo;MASS\u0026rdquo;, \u0026ldquo;car\u0026rdquo;, and \u0026ldquo;easyanova\u0026rdquo; packages.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Root architecture\u003c/h2\u003e \u003cp\u003eStudy of the root systems showed that the interaction effects on NLR were significant (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.01\u003c/em\u003e). Based on the results, different treatments showed varying responses in terms of NLR, NWDP and NWCA. Plants from which 3 mm of the radicle tip was removed (CS3) when the radicle length reached 2\u0026ndash;3 cm (L3) had significantly higher numbers (n\u0026thinsp;=\u0026thinsp;32) of lateral roots. By increasing seedling root lengths to L4 (3\u0026ndash;4 cm) and L5 (4-5cm), lateral root numbers (NLR) decreased. No significant difference was found between L1CS1, L1CS5 and the uncut control. These displayed the lowest NLR (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eThe root network convex area.\u003c/b\u003e NWCA was lowest in L1CS1 and did not differ significantly from the control, L1CS3, and L1CS5 treatments. The greatest NWCA belonged to the L3CS3, which also had the highest number of lateral roots. NWCA ascended from L1 to L3 but, when the length of the radicle reached to L4 and L5 and the cutting was done, NWCA decreased (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003eNetwork depth.\u003c/b\u003e The impact of radicle-tip cutting on NWDP showed that the L3CS1 treatment had the highest NWDP and no significant difference existed between the control and this treatment. The L1CS5 treatment had the lowest NWDP (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eRoot network volume.\u003c/b\u003e NWVL was significantly influenced by radicle length and cut size \u0026times; radicle length interaction (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.01\u003c/em\u003e). The L3CS3 treatment resulted in the highest NWVL. Radicle lengths of 0.5-1 cm were deemed unsuitable for cutting, as they led to a reduction in lateral root numbers. Control plants exhibited similar NWCA and NWVL to those cut at L1 length with no significant difference between them (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eNetwork length distribution.\u003c/b\u003e Root architecture data indicated that NWLD was significantly affected by radicle length (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.01\u003c/em\u003e) and size of the cutting site (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.0\u003c/em\u003e5), as shown in the root architecture data. Control plants displayed the highest NWLD, comparable to L3CS3 and showed no significant differences.\u003c/p\u003e \u003cp\u003e \u003cb\u003eEllipse aspect ratio\u003c/b\u003e. ELAX was unaffected by the treatments, with only the interaction of radicle length \u0026times; cut size proving significant (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e). Control plants exhibited the highest NWLD. There were no significant differences in NWLD between L1 and L5 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Growth characteristics\u003c/h2\u003e \u003cp\u003eThe results revealed significant impacts of the studied treatments (\u003cem\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.01\u003c/em\u003e) on the FW and DW of shoot and root. The lowest FW and DW for both shoot and root were observed in L5CS5 and L1CS5 treatments. Differences occurred in the height of \u003cem\u003eP. vera\u003c/em\u003e seedlings across treatments, with the tallest plants (22.6 cm) achieved through the L3CS3 treatment. Control plants had an average height of 9.6 cm, surpassing the L1 treatments (L1CS1, L1CS3, L1CS5) and L5CS5 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In addition, the L3CS3 treatment demonstrated significantly higher leaf area, FW and DW for both root and shoot compared to the other treated seedlings and control. This treatment proved to be the most effective in terms of growth parameters, including the induction of lateral roots and root architecture parameters.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean values for plant height, leaf area, ellipse axes ratio, and network length distribution in pistachio seedlings under radicle-tip cutting treatments\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"7\" nameend=\"c9\" namest=\"c3\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRadicle length (L)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCut size (CS)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ePlant height (cm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eLeaf area (cm2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003eELAX\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003eNWLD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eL1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.5 jk\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.28 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.2 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.13 g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.83 j\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.65 gh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.13 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.2 fg\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 k\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.28 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.22 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.13 g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eL2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.6 d-f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.4 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.54 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.37 de-g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.3 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.06 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.3 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.53 b-d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.33 gh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.11 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.3 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.43 c-f\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eL3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.33 cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.11 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.324 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.54 b-d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.6 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.71 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.284 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.7 ab\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 f-h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.46 b-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.33 b-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.65 bc\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eL4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 fg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.55 e-g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.37 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.53 b-d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.69 d-f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.374 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.48 b-e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.66 ij\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.49 e-g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.394 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.45 b-e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eL5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.66 hi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.98 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.36 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.34 d-g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.5 e-g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.65 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.304 c-e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.26 e-g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eCS5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.33 k\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.86 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.355 b-d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.194 fg\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eControl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.66 ij\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.89 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.932 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.92 a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003ens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003ens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eL\u0026times;CS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e \u003cp\u003eELAX: ellipse aspect ratio, NWLD: network length distribution. L: the length of the radicle when its tip is being cut including 0.5-1 (L1), 1\u0026ndash;2 (L2), 2\u0026ndash;3 (L3), 3\u0026ndash;4 (L4) and 4\u0026ndash;5 cm (L5); CS: the length of cutting site from radicle tip including 1 (CS1), 3 (CS3) and 5 mm (CS5). C: control (no cutting)\u003c/p\u003e \u003cp\u003e*, **, ns: Significant differences at 5% and 1% probability levels and non-significantly different, respectively.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Plant vitality\u003c/h2\u003e \u003cp\u003eThe L2, L3, and L4 treatments, along with the control group, displayed the highest level of vitality and a lower number of necrotic leaves. In contrast, the plants subjected to L5 and L1 treatments showed the lowest vitality, with a score of 1 (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eRoot architecture plays a crucial role in the establishment and survival of plants in the field, emphasizing the reliance of plant establishment on root structure (Half, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Root architecture is developed by combining the growth of existing roots and their tropism (for growth) with LR speed and position (Guyomarc\u0026rsquo;h et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Well-developed roots in seedlings accelerate progress during acclimatization post-transplantation and reduce the time needed to reach the grafting stage(Vahdati et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). This study aims to optimize radicle cutting in pistachio trees to enhance seedling establishment during orchard initiation..\u003c/p\u003e \u003cp\u003ePistachio root systems often lack lateral root production (Ferguson et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), increasing transplantation costs and reducing survival rates. Altering pistachio Root System Architecture (RSA) during the initial stages of seedling growth in the nursery would require less labor, lower costs, and improve survival in the field. Success of lateral root induction depends on external (changing environment, human manipulations) and internal (phytohormones) factors (Aloni et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Larue et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Pinching or halting radicle growth, which is applied to overcome apical dominance, allows the production of lateral roots (Kumar, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Our results demonstrate that the success of root tip cutting depends on radicle length and cut site size. Optimal results were observed when the radicle length reached 2\u0026ndash;3 cm, leading to improved growth, root architecture, and overall plant survival. However, any deviation away from this range, whether less or more, resulted in diminished growth indices.\u003c/p\u003e \u003cp\u003eCell division, primarily in the apical meristem, slows as it progresses to the elongation (EZ) and differentiation zones (DZ). Lateral roots originate from mature pericycle layer cells, a process potentially enhanced by removing the root tip, possibly through a cytokinin connection. Another potential mechanism, similar to what we observed in our findings, that could enhance the quantity of lateral roots is removal of the the root tip, possibly through its connection to cytokinin (Aloni et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Cytokinins (CK) and indole-3-acetic acid (IAA) have antagonistic roles in the formation of lateral roots. Auxin promotes lateral root formation (Du and Scheres, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Cytokinin concentration in the root tip determines the initiation of lateral root formation. A high concentration of CK in the root cap prevents formation of lateral roots in the root cap. Thus, lateral root initiation is located further from the root cap, where the CK concentration are lower (Aloni et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Hence, root tip removal, especially in meristematic points, increases lateral root formation (Sorin et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Our findings revealed that the maximum NLR was obtained by cutting 3 mm from the radicle tip. The density of meristematic cells is higher in this area. Our results parallel and support those of Orhan et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), who reported that radicle-tip cutting-treated seeds had significantly more lateral roots than controls.\u003c/p\u003e \u003cp\u003eManipulating root system architecture enhances water and nutrient efficiency, improving plant survival in challenging soils. Root system architecture (RSA) has many effects on growth and final product performance (de Dorlodot et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Increased lateral roots boost total root area, mechanical strength, and soil exploration (Nibau et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In our study, NWCA also increased with the increasing NLR. With an increase in root NWCA and NWDP, the plant has more access to water and food, a direct link to increased growth and performance (Nibau et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Passot et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). In the other words, our results showed that by manipulating the root architecture and increasing the number of lateral roots and then the root volume, plant vitality and growth characteristics improved.\u003c/p\u003e \u003cp\u003eThe observed enhancement in growth parameters can be attributed to an increase in elemental uptake facilitated by the development of lateral roots. Architectural modifications of the root system in response to phosphate is important for plant nutrition. The main adaptive feature for phosphate access is the ability to detect different layers near the soil surface through changes in RSA (de la Riva et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Phosphate deficiencies cause growth signals to shift focus from the PR to LRs. Growth of the PR inhibits LR elongation and suppresses initiation before emergence of a highly-branched, shallow root system. This evolutionary adaptation slows growth in deeper soils where nutrients are limited and redirects resources to root exploration of nutrient-rich topsoil and plant growth (Nibau et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eLateral roots existing prior to tip excision were stimulated but slow to grow. In contrast, lateral roots developing after tip excision showed rapid, unchecked lateral growth, extending nearly to the length of taproots but no deeper (Hankin and Watson, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This study may be useful for seedlings with lateral root deficiencies and low survival rates after transplantation. Only pericycle cells previously primed in the basal meristem go on to form lateral roots (Malamy and Benfey, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1997\u003c/span\u003e). A series of coordinated periclinal cell divisions lead to the formation of a lateral root primordium (De Smet et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe study suggests that the distance between the cells increases as the radicle grows. The L3CS3 treatment disrupts the meristematic cell area, stimulating the radicle to become multi-branched. Therefore, with the age and increased distance of the radicle from the meristem zone, fewer lateral roots will be formed. In terms of cellular activity, cell division occurs in the meristem zone, and mature cells in the pericycle layer give rise to lateral roots.\u003c/p\u003e \u003cp\u003eThis study recommends the 3 mm distance for root tip excision to maximize meristem cells and increase lateral root numbers. As this work showed a significant increase in survival following transplantation, this study can serve as a foundation and starting point for investigations into other species with low post-transplantation survival rates. Therefore, mechanizing this technique can be considered for future studies aimed at reducing labor costs, increasing the chances of transplantation survival, and better establishment of pistachio plants in the orchard.\u003c/p\u003e"},{"header":"5 Conclusion","content":"\u003cp\u003eThe transplantation of pistachio trees often faces challenges due to damage to their main root tip. Consequently, alterations in the root structure and enhanced lateral root formation are likely to reduce seedling mortality and enhance the establishment and initial growth of the seedlings. This is the first study to demonstrate the most appropriate time and desirable cut size for inducing lateral roots in pistachio. Our results confirm that optimizing the radicle-tip cutting technique by focusing on the cutting time and length of the radicle-tip cutting site not only alters the root architecture to promote root branching, but also enhances the plant's vitality and initial growth. Our findings affirm that the success of root tip removal depends on two factors: the length of the radicle when its tip is being cut and the size of the cutting site. We found that root architecture, growth, and plant vitality were improved when the length of the radicle-tip cutting is 2\u0026ndash;3 cm (L3). For optimal results, we recommend removing 3 mm from the radicle tip (as this area contains a higher concentration of meristematic cells) when its length is 2\u0026ndash;3 cm. In essence, the L3CS3 treatment disrupts the meristematic region, promoting increased lateral root development. These findings offer valuable insights to pistachio nurseries, aiding in minimizing seedling losses during transportation and obtaining seedlings with robust root systems.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting Interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contributions\u003c/h2\u003e \u003cp\u003eConceptualization: M.R.R and S.S; methodology: M.R.R and S.S. and M.O.; software: M.O.; validation: M.R.R; S.S., M.M.A; writing original draft preparation: M.O; writing review and editing: M.O; M.R.R; S.S., S.L., M.M.A, R.S.M and K.V. visualization: M.O, S.S.; supervision: M.R.R; S.S. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAfrousheh, M., Javanshah, A., 2020. 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Plants 10 (11), 2234. https://doi.org/10.3390/plants10112234.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Growth parameters, Lateral roots, Pistacia vera L., Root architecture, Transplanting","lastPublishedDoi":"10.21203/rs.3.rs-4755928/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4755928/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eRoot architecture critically influences plant growth and survival. Pistachio plants face challenges because of the limited lateral roots within a taproot system and the poor survival rates if the primary root tip is severed during transplantation. This study investigated the effects of radicle-tip cutting (RC) on lateral root formation and growth of \u003cem\u003ePistacia vera\u003c/em\u003e L. \u0026lsquo;Ohadi\u0026rsquo; seedlings. A factorial experiment with varying radicle lengths (L1-L5) and cutting site portions (CS1-CS5) was conducted. Control plants had an intact radicle tip. Following treatment, seedlings were transferred to 2 L pots filled with perlite, and nourished weekly with half-strength Hoagland's solution. After nine weeks, growth parameters and root characteristics were assessed. Results indicated that optimal radicle-tip cutting occurred at a radicle length of 2\u0026ndash;3 cm (L3), with an ideal cutting distance of 3 mm from the radicle-tip (CS3). This treatment (L3CS3) led to improved growth (plant height, leaf area, shoot fresh weight (FW), root FW, shoot dry weight (DW), root DW) and root architecture (number of lateral roots (NLR), network depth (NWDP), network volume (NWVL), network convex area (NWCA) parameters, enhancing plant vitality. These findings offer valuable insights for nurserymen aiming to produce pistachio seedlings with robust lateral roots and higher post-transplantation survival rates.\u003c/p\u003e","manuscriptTitle":"Optimizing radicle-tip cutting for improved growth and lateral root formation in pistachio seedlings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-29 19:06:27","doi":"10.21203/rs.3.rs-4755928/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"84277d2f-6aa1-4adf-a9f8-2848858bccab","owner":[],"postedDate":"August 29th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-25T10:52:41+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-29 19:06:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4755928","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4755928","identity":"rs-4755928","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}