Mycorrhizal-specific responses of rhizosphere soil properties and fine-root traits to polystyrene microplastic addition in a temperate mixed forest

Mycorrhizal-specific responses of rhizosphere soil properties and fine-root traits to polystyrene microplastic addition in a temperate mixed forest | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Mycorrhizal-specific responses of rhizosphere soil properties and fine-root traits to polystyrene microplastic addition in a temperate mixed forest Cunguo Wang, Yingtong Zhou, Ivano Brunner, Ziping Liu, Wei Guo, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6627952/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Jan, 2026 Read the published version in Communications Earth & Environment → Version 1 posted You are reading this latest preprint version Abstract While the impacts of microplastics on aquatic and agricultural ecosystems are well studied, the impacts on forest ecosystems involving soil and trees are scarcely investigated. Here, we assessed the impacts of microplastic addition on rhizosphere soil properties, and chemical, morphological and anatomical traits of fine roots for ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species in a mixed temperate forest. We found that the concentration of available nitrogen in the soil rhizosphere increased, while the concentration of available phosphorus decreased in the ECM tree species after the addition of microplastics. The opposite pattern was true for AM tree species. Fine roots of ECM tree species exhibited shorter root length, smaller root diameter, lower root tissue density, lower branching ratio, lower branching intensity, and lower phosphorus concentration, but higher hyphal density, higher root carbon/nitrogen, and higher root carbon/phosphorus ratios with the addition of microplastics mediated by total phosphorus in the soil. Fine roots of AM tree species exhibited higher specific root length, tip density, epidermal thickness, vascular bundle diameter and root carbon/nitrogen ratio, but lower root diameter, branching intensity, cortical thickness, root tissue density and root phosphorus concentration after microplastic addition, which was mediated by soil water content, nitrate nitrogen and available phosphorus. These findings on mycorrhizal-specific responses to microplastic addition will deepen our understanding of carbon and nutrient cycling and species composition dynamics with increasing microplastic pollution in temperate mixed forest ecosystems. Earth and environmental sciences/Biogeochemistry/Element cycles Earth and environmental sciences/Ecology/Forest ecology arbuscular mycorrhizal ectomycorrhizal nitrogen nutrient acquisition strategy phosphorus Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Microplastics, defined as plastic particles smaller than 5 mm in diameter, are formed by plastic polymers under the influence of light, mechanical abrasion and temperature fluctuations 1 , 2 . While the effects of microplastics on aquatic ecosystems are well studied, the effects on terrestrial ecosystems, especially on plants, are only gradually being researched 3 . Microplastics, which are known for their corrosion resistance, are widely distributed in terrestrial ecosystems, including forest soils, and remain in the environment for long periods of time 1 , 4 – 7 . Forests can effectively filter atmospheric microplastics, with intercepted particles accumulating in organic layers of forest soils before leaching into mineral soils 8 – 10 . Microplastics impair the cohesion between soil aggregates, which in turn alters physical properties such as water retention capacity and bulk density, the availability of nutrients in the soil and their uptake by plants, and increases oxidative stress, which ultimately induces toxicity that affects photosynthesis and plant growth 11 – 13 . The ability of trees to acquire soil nutrients under microplastic accumulation will influence forest composition and function in a changing world. In general, the efficiency of resource acquisition by trees is optimized by the plasticity of root morphology (e.g., root length) and anatomy (e.g., cortical thickness) in forest ecosystems 14 , 15 . A recent meta-analysis indicated that microplastics can reduce root biomass and root length 16 . The negative effects of microplastic on roots can be that it blocks the cell junctions or the cell wall, mechanically damages the roots and leads to a decrease in root activity and hinders the general growth of the roots 17 – 19 . The metabolic costs of fine roots (fine root respiration) are major factors that prevents plants from efficiently exploring the soil and absorbing nutrients under unfavorable conditions 20 . Thus, increasing the stele diameter of roots (which have a lower metabolic rate) and/or the reducing the cortical thickness of roots (which have a higher metabolic rate) can reduce fine root respiration and nutrient demand (e.g., lower root nitrogen concentration) and thus increase the resource acquisition efficiency of plants in microplastic-polluted soils 21 , 22 . It is concluded that root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees 23 . Although arbuscular mycorrhizal (AM) fungi cannot reduce the absorption of microplastics by plants, they can immobilize microplastics in vesicles and hyphae, and enhance the resistance of plants to microplastics by altering the chemical characteristics of microplastics, such as reducing their complexation 20 . Thus, tree associations with AM fungi may be able to alleviate the direct stress associated with the addition of microplastic in soil 19 , 24 , 25 . The altered habitat caused by the addition of polyester microplastic led to the colonization of the roots by AM fungi, which conferred positive effects on plant growth by increasing nutrient availability 26 . Moreover, it is noted that ectomycorrhizal (ECM) fungi have the ability to mobilize nutrients from organic forms 27 – 29 . Thus, we speculate that roots of trees associated with ECM fungi can overcome nitrogen and phosphorus limitation induced by microplastic accumulations in soils 30 . However, interactions of microplastics with roots of ECM trees have been not understood in temperate forest ecosystems 31 . Given the contrasting roles of AM and ECM fungi on carbon and nutrient cycles 32 , 33 , the unresolved mechanisms underlying AM and ECM tree responses to microplastics strongly restrict our understanding of how trees shift their allocation of resources to different nutrient acquisition strategies under increasing microplastic deposition in forest ecosystems 34 , 35 . A recent study has indicated that the Changbai mountains have the highest deposition of microplastics in seasonal snow in north-east China 34 . Here, we quantified the microplastic-induced alterations in soil properties in the rhizosphere and the morphological, chemical and anatomical adaptations of fine roots between AM and ECM tree species after the addition of microplastics in a mixed Pinus koraiensis forest in the Changbai mountains. We hypothesize that (1) the negative impacts of microplastic addition on soil properties are specific to mycorrhizal associations, and that (2) the two mycorrhizal tree species (AM versus ECM) would show different strategies for the acquisition of root resources under microplastic addition. In particular, AM tree species would pursue a more proactive root exploration strategy compared to ECM tree species, which would demonstrate enhanced mycorrhizal symbiosis for resource acquisition under microplastic addition. Result We found that mycorrhizal type, microplastic addition and their interactions significantly affected most of soil properties, expect for SCN (for mycorrhizal type), (for microplastic addition) and pH (for mycorrhizal type and microplastic addition), as well as TP and SCN (for the interactions of mycorrhizal type and microplastic addition; Table 1). Specifically, microplastic addition significantly increased TC, TN, AN, , and SWC of ECM tree species, but decreased the corresponding properties of AM tree species (Figure 1). ECM tree species significantly decreased TP, leading to increases in SCP and SNP under microplastic addition (Figure 1c, e, f). Soil pH and AP of ECM tree species significantly decreased, but those of AM tree species increased following microplastic addition (Figure 1j, k). We observed that mycorrhizal type significantly affected RC, RN, RP, RCN, RCP, RNP, RTD, TD and HD, while microplastic addition significantly affected RC, RN, RCN, RCP, RL, BI and HD. Meanwhile, RC, RP, RCP, BR and HD were significantly influenced by the interactions of mycorrhizal type and microplastic addition (Table 2). Specifically, RC and RCN of both ECM and AM tree species were significantly higher in microplastic addition treatment than in CK (Figure 2a, d). RN of AM tree species significantly decreased, while RP of ECM tree species significantly decreased under microplastic addition (Figure 2b, c). Microplastic addition significantly increased RCP of ECM tree species but decreased RNP of AM tree species (Figure 2e, f). Microplastic addition significantly decreased RL, RD, RTD, BR, BI and FD of ECM tree species, while increased HD. Conversely, AM tree species significantly increased SRL, TD, ET and VBD, but decreased RTD, BI, FD and CT following microplastic addition (Figure 3). Mantel test analysis showed that morphological, chemical and anatomical traits of fine roots, as well as hyphal density for ECM tree species were more associated with soil properties than AM tree species. Root anatomy and morphology of ECM tree species was related to TP, pH and , while that of AM tree species was related to AP, and (Figure 4). Furthermore, redundancy analysis showed that TP, as well as , SWC and AP were the strongest determinant of root traits in ECM and AM tree species, respectively (Figure 5). Principal component analysis showed that the first two principal components explained 59.3% of the variance in root traits (Figure 6a). Root anatomical and morphological traits (expect for RTD) mainly loaded on the first principal component, while root chemical traits and RTD on the second principal component (Figure 6a). ECM and AM tree species were clearly differentiated by the second principal component (Fig. 6b), which was confirmed by differences in the scores along the first and second principal components between ECM and AM tree species (Figure 6c, d). Table 1 . Effects of mycorrhizal type (MT), microplastic addition (MP) and their interactions (MT × MP) on soil properties using two-way ANOVAs. F values are given. Factors df TC TN TP SCN SCP SNP AN AP pH SWC MT 1 235 *** 306 *** 13.7 ** 0.24 10.6 *** 21.9 *** 16.4 *** 52.1 *** 122 *** 91.9 *** 0.01 326 *** MP 1 26.1 *** 12.4 ** 12.3 ** 36.9 *** 18.4 *** 20.2 *** 6.38 * 0.15 10.3 ** 59.0 *** 0.07 154 *** MT × MP 1 254 *** 347 *** 2.22 0.36 35.2 *** 49.4 *** 29.8 *** 29.2 *** 145 *** 112 *** 24.7 *** 296 *** Residuals 20 0.01 0.00 0.02 0.00 0.03 0.02 0.17 0.07 0.03 0.04 0.00 0.01 df, degree of freedom; TC, soil total carbon concentration (g kg -1 ); TN, soil total nitrogen concentration (g kg -1 ); TP, soil total phosphorus concentration (g kg -1 ); SCN, the ratio of soil total carbon concentration to soil total nitrogen concentration; SCP, the ratio of soil total carbon concentration to soil total phosphorus concentration; SNP, the ratio of soil total nitrogen concentration to soil total phosphorus concentration; , soil nitrate nitrogen concentration (mg kg -1 ); , soil ammonium nitrogen concentration (mg kg -1 ); AN, soil available nitrogen concentration (mg kg -1 ); AP, soil available phosphorus concentration (mg kg -1 ); pH, soil pH; SWC, soil water content (%). *** P < 0.001; ** P < 0.01; * P < 0.05. Significant P -values (<0.05) are in bold. Table 2 . Effects of mycorrhizal type (MT), microplastic addition (MP) and their interactions (MT × MP) on chemical, morphological and anatomical traits of fine roots, as well as hyphal trait using two-way ANOVAs. F values are given. Chemical traits Morphological traits Hyphal trait Anatomical traits Factor df RC RN RP RCN RCP RNP RL RD SRL RTD BR BI TD HD 8.61 ** 21.0 *** 8.73 ** 0.06 FD ET CT VBD MT 1 30.0 *** 46.7 *** 12.1 ** 29.6 *** 36.8 *** 100 *** 1.17 1.24 2.68 5.56 * 0.36 3.87 6.18 * 0.58 0.00 1.65 1.01 MP 1 46.3 *** 4.67 * 0.93 24.2 *** 15.7 *** 1.89 5.46 * 0.30 0.08 3.73 2.15 8.14 ** 0.27 0.58 1.03 1.92 0.14 MT × MP 1 25.2 *** 1.25 0.62 * 0.43 9.00 ** 3 .34 0.47 0.15 1.58 0.01 5.78 * 0.61 0.86 0.01 0.30 0.24 0.33 Residuals 20 0.00 0.01 0.01 0.01 0.01 0.01 0.13 0.05 0.22 0.04 0.03 0.19 0.58 0.12 0.22 0.17 0.12 df, degree of freedom; RC, root carbon concentration (%); RN, root nitrogen concentration (g kg -1 ); RP, root phosphorus concentration (g kg -1 ); RCN, root carbon concentration to root nitrogen concentration; RCP, root carbon concentration to root phosphorus concentration; RNP, root nitrogen concentration to root phosphorus concentration. RL, root length (cm cm -3 ); RD, root diameter (mm); SRL, specific root length (cm g -1 ); RTD, root tissue density (g cm -3 ); BR, branching ratio; BI, branching intensity (no cm -1 ); TD, tip density (no cm -3 ); HD, hyphal density (m g -1 ); FD, the diameter of first-order roots (mm); ET, epidermal thickness (mm); CT, cortical thickness (mm); VBD, vascular bundle diameter (mm). *** P < 0.001; ** P < 0.01; * P < 0.05. Significant P -values (<0.05) are in bold. Discussion Impacts of microplastics on soil properties of ECM and AM tree species We found that rhizosphere soil of ECM tree species significantly increased nitrogen availability, but decreased phosphorus availability following microplastic addition (Fig. 1 ). The accumulation of inorganic nitrogen such as nitrate and ammonium nitrogen are dependent of its balance between production (e.g. nitrification and mineralization) and depletion (e.g. denitrification and microbial immobilization) 36 . It is widely accepted that ECM fungi have the ability to obtain nitrogen from organic forms 37 , 38 . We expected that microplastic accumulation in soils appears to amplify the ECM symbiotic nitrification and nitrogen mineralization efficiency, resulting in increased concentrations of nitrate and ammonium nitrogen in the rhizosphere soil of ECM tree species 39 , 40 . However, the available phosphorus of ECM tree species was found to be lower after the addition of microplastics in the mixed forest, partially supporting our first hypothesis, which is consistent with a recent meta-analysis 41 . These findings potentially suggest the negative effects of microplastics on phosphorus mineralization of ECM fungi by reducing phosphatase activity 42 , 43 . Furthermore, microplastic addition significantly increased soil water content of ECM tree species, which is due to the fact that microplastics can be an obstacle to evaporation and can change soil bulk density 26 , 44 . At the same time, we observed that soil water content was negatively related to the available phosphorus of ECM tree species (Fig. 4 a), confirming the statement that microplastics are likely to exacerbate soil phosphorus leaching 41 , 45 , 46 . This is also supported by the lower soil total phosphorus of ECM tree species (Fig. 1 ). Compared to the ECM tree species, we found lower available nitrogen, especially nitrate nitrogen, but higher available phosphorus in the rhizosphere soil of the AM tree species under microplastic addition in the mixed forest, which supports our first hypothesis (Fig. 1 ). Our results of the negative effects of microplastic on nitrate nitrogen are in accordance with previous findings 36 . We observed that AM tree species significantly increased the ratio between soil total carbon concentration and soil total nitrogen concentration after the addition of microplastics, while ECM tree species did not (Fig. 1 ). The higher carbon to nitrogen ratio caused by microplastics may enhance nitrogen immobilization by microbes, leading to the decreased inorganic nitrogen accumulation in rhizosphere soil of AM tree species 36 . These findings are also supported by the significantly negative relationships of the carbon to nitrogen ratio and the available (ammonium) nitrogen (Fig. 4 b). Furthermore, we speculate that the addition of microplastics may reduce the relative abundance of nitrifiers involved in nitrification, which partly explains the lower soil nitrate nitrogen and higher soil pH of AM tree species (Fig. 1 ), as the nitrification process leads to a low soil pH 36 , 47 . It is indicated that AM fungi enhance the resistance of plants to microplastics through transforming the chemical properties of microplastics, and promoting phosphorus nutrition at high microplastic addition levels 20 . Microplastic addition may possibly lead to phosphorus mobilization from inorganic and organic sources 48 . The increase of phosphatase activity under exposure to microplastics promotes the decomposition and transformation of organophosphorus compounds, leading to a significant increase in soil inorganic phosphorus 49 , 50 . In summary, our findings suggest that the effects of microplastic pollution on soil nutrients in forest ecosystems may be mycorrhiza-specific, although the underlying mechanisms are not yet fully understood (Fig. 7 ). Impacts of microplastics on root traits of ECM and AM tree species In this study, we observed the consistent responses of root chemical traits to microplastic addition for ECM and AM tree species, with the higher root carbon to nitrogen ratio, as well as root phosphorus or root nitrogen concentration (Fig. 2 ). Our findings indicate that microplastics have a detrimental effect on root nutrient contents, although more available nitrogen and phosphorus were found in the rhizosphere soil of ECM and AM tree species, respectively (Fig. 1 ). Microplastics that adhere to fine roots can clog pores and channels and thus impair root growth 51 , 52 . Indeed, microplastics have negative impacts on root tissues and directly damage the morphology of root cells, which further reduces the nutrient uptake of plant roots 53 . This assertion is supported by our findings that the diameter of first-order roots and the density of root tissue of the entire root system is lower in ECM and AM tree species under microplastic addition (Fig. 3 ). In combination with a reduced soil bulk density through microplastic addition it can be expected that fine roots experience a reduced penetration resistance, thus decreasing the diameter of fine roots 54 . However, the lower diameter and root tissue density indicate that root lifespans are shorter, reflecting the microplastic accumulation in soils potentially enhances the carbon input from plants into the soil through root turnover in forest ecosystems. Our results provide evidence that trees differentially modify their root morphological traits under microplastic addition depending on their dominant mycorrhizal associations, which is in line with our second hypothesis. Generally, mycorrhizal symbiosis (allocating carbon to mycorrhizal fungi) and root exploration (allocating carbon to fine root system expansion) are considered as two root nutrient acquisition strategies that trees use to forage for soil resources 38 . Overall, it can be observed that ECM tree species produce root systems with shorter root length, lower branching ratio and lower branching intensity, but denser hyphae under microplastic accumulation in soils (Fig. 3 ), indicating a switch in the nutrient acquisition mechanism from root exploration to mycorrhizal symbiosis. We speculate that the increased carbon allocation to mycorrhizas by ECM tree species under microplastic addition is related to the ability of ECM fungi to mobilise organic nutrient 55 , 56 . This indicates that ECM trees may enhance their response to external environmental stress by enhancing the extent of mycorrhizal hyphae in unfavorable soil environments 57 , 58 . Therefore, ECM tree species may rely on mycorrhizal associations with their roots to acquire soil nutrients, specifically for phosphorus in microplastic polluted soils in forest ecosystems (Fig. 7 ). We observed different responses to the addition of microplastics in AM tree species, where specific root length and tip density increased, whereas in ECM tree species these parameters did not change (Fig. 3 ), which may suggest that AM tree species adopt a root-dependent strategy under microplastic accumulation in soils in forest ecosystems. Higher specific root length can facilitate rapid nutrient foraging (specifically for inorganic nitrogen) at lower carbon costs 59 , 60 . Meanwhile, cortical thickness of roots of AM tree species decreased under microplastic addition, while that for ECM tree species did not (Fig. 3 ), indicating a reduced mycorrhizal colonization potential of AM tree species. These findings provide evidence that carbon allocation to mycorrhizal fungi may be downregulated by AM tree species under microplastic accumulation in soils. Concurrently, AM tree species exhibit synchronized increases in epidermal thickness and vascular bundle diameter under microplastic addition. The thickened epidermis may reduce mechanical damage caused by microplastics, while the enlarged vascular bundle diameter can offset hydraulic losses resulting from decreased root tissue density 61 . Thus, AM tree species invested more in the absorption and transport capacity of their own root system and in defense mechanisms than in symbiotic strategies associated with the absorptive roots of ECM tree species (Fig. 7 ). Regulation of the responses of root traits to microplastic addition for ECM and AM tree species Both the mantel test analysis and the principal component analysis demonstrated significant differences in the associations of morphological, chemical and anatomical root traits to soil properties between ECM and AM tree species under microplastic addition (Figs. 4 , 6 ). Furthermore, redundancy analysis showed that soil total phosphorus, as well as nitrate nitrogen, available phosphorus and soil water content emerged as key constraints on root traits of ECM and AM tree species, respectively (Fig. 5 ). As mentioned above, microplastic addition results in declines in total and available phosphorus in rhizosphere soil of ECM tree species, thereby limiting root phosphorus absorption 62 , 63 . This is confirmed by the lower root phosphorus concentration of ECM tree species (Fig. 2 ). In contrast, AM tree species may experience greater nitrogen limitation in microplastic polluted environments due to their greater reliance on unstable soluble nitrogen pools and lack in saprotrophic capacity to access complex organic nitrogen compared with ECM tree species 33 , 64 . Reduced root nitrogen coupled with stable root phosphorus increase root nitrogen to phosphorus ratio, indicating faster nitrogen loss rate than phosphorus of AM tree species 65 . Indeed, it has been repeatedly demonstrated that AM fungi can dominate phosphorus uptake in symbiotic plants, and in several plant-AM fungus associations, a nearly 100% contribution of the mycorrhizal pathway to the overall phosphorus uptake was estimated 66 , 67 . Moreover, AM tree species are more sensitive to drought stress than that of ECM 68 , 69 . Thus, microplastic-induced declines in soil water content can exacerbate AM fungal vulnerability, as hydraulic efficiency governs the performance of the symbiosis under drought conditions 33 , 68 . In summary, these findings highlight the different role of soil properties in regulating root adaptations to microplastic accumulation in soils of different mycorrhizal types in this mixed forest. Conclusion This study suggests that the addition of microplastics affects the soil properties of the rhizosphere of ECM and AM tree species in the mixed forest in Changbai mountains differently. The nitrogen availability of the rhizosphere soil increased significantly, but the phosphorus availability decreased after the addition of microplastics in ECM tree species. In contrast, AM tree species showed an opposite response pattern to the addition of microplastics, with a lower concentration of available nitrogen but a higher concentration of available phosphorus in the rhizosphere soil. Together with the results of root chemical trait responses to microplastic addition, our findings indicate that microplastics were detrimental to nitrogen and phosphorus uptake by roots of ECM and AM tree species in forest ecosystems. Moreover, ECM tree species tended to produce root systems with lower root length, root diameter, root tissue density, branching ratio, branching intensity but higher hyphal density under microplastic accumulation in soils, while AM tree species tended to produce root systems with higher specific root length, tip density, epidermal thickness and vascular bundle diameter, but branching intensity, cortical thickness and root tissue density. Accordingly, our results provide evidence that ECM and AM tree species exhibited two divergent nutrient acquisition strategies, mediated by soil total phosphorus, as well as by soil water content, nitrate nitrogen and available phosphorus, respectively. Overall, these findings highlight that microplastic pollution disrupts nutrient acquisition pathways differently in ECM and AM trees, which has a strong impact on carbon and nutrient cycling, as well as on the dynamics of tree species composition in temperate mixed forest ecosystems. Materials and methods Study site The study site (42°24′N, 127°47′E, 738 m above sea level) is located in a mixed mature P. koraiensis forest within the Changbai Mountain Nature Reserve in Jilin province, China. In this region, the mean annual air temperature is 3.5°C, and the highest and lowest monthly mean air temperatures appear in August (20.5°C) and January (− 16.5°C), respectively. The mean annual precipitation is 740 mm. The soil has developed from volcanic ash and is classified as Eutric cambisol with a high organic matter content in the surface layer. The mixed mature forest is dominated by the coniferous species P. koraiensis and broad-leaved tree species such as Tilia amurensis , Fraxinus mandshurica , Phellodendron amurense , Juglans mandshurica and Acer mono . This forest exhibits a complex multi-layered structure and represents the typical zonal climax vegetation of the humid mountain areas in northeastern China. In this study, the four tree species P. koraiensis (ECM), T. amurensis (ECM), P. amurense (AM), and J. mandshurica (AM) were selected to investigate the responses of rhizosphere soil properties and root traits of different mycorrhizal types to the addition of microplastics. Experimental design In this study, we used the root bag method 70 to isolate roots of different tree species in the mixed forest. In early May 2023, woody coarse roots (25 cm long, ~ 5 mm in diameter) were excavated from selected trees without cutting them off. All fine and lateral roots were then removed at the distal end before the trimmed roots were placed into polyester root bags (30×30 cm, 0.5 mm mesh). To obtain 1% (w/w) microplastic treated soil, we previously mixed 1.25 kg of polystyrene particles (100 µm in diameter; Dongguan Xinchangqiao Plastic Co., Ltd., China) thoroughly with 125 kg of soil (sieved fresh soil collected from the 0–20 cm forest floor layer). A total of 48 polystyrene-treated root bags (microplastic addition “MP”, 2.5 kg of polystyrene treated soil) were prepared (4 bags per tree individual × 3 individuals per tree species × 4 tree species), while the control bags (“CK”, 48 bags) were filled with soil in the same manner but without the addition of polystyrene particles. The root bags were then reburied in the original forest soil, covered with the pre-existing leaf litter layer, and wetted with water. In late September 2023, we retrieved the root bags by cutting the woody roots at the bag entrance. The collected bags were immediately stored in a refrigerated container and transported to the laboratory. Root samples were carefully removed from each root bag, and rhizosphere soil was collected by gently shaking off adhering soil. For anatomical analysis, the root samples with intact fine root branches were fixed in a formalin-acetic acid-ethanol solution (90 ml of 70% ethanol, 5 ml of 100% glacial acetic acid, 5 ml of 38% formaldehyde). The root and soil samples were kept under cold conditions at 4°C for subsequent analyses. Root trait measurements After cleaning the root surfaces, we scanned the samples into image files using an Epson Perfection V700 root scanner (1200 dpi resolution). The images were then analyzed using root analysis software (WinRhizo, Regent Instruments Inc., Quebec, Canada) to determine average root diameter (RD), average root volume and root length (RL). Branching ratio (BR) was defined as the number of first-order roots divided by the number of second-order roots. Branching intensity (BI) was calculated as the number of first-order roots per unit length (cm) of second-order roots. Root tip density (TD) was quantified as the number of root tips per unit volume (cm³) of soil. The scanned roots were subsequently placed in paper bags and oven-dried. The oven temperature was initially set to 105°C for 30 minutes, then reduced to 65°C until a constant dry weight was achieved and weighted. Specific root length (SRL) was defined as root biomass per unit root length, while root tissue density (RTD) was defined as root biomass per unit root volume. After grinding, we sieved the root samples through a 100 µm-mesh screen and stored them in bags for chemical analysis. Root carbon content (RC) and root nitrogen content (RN) were measured using an elemental analyzer (EURO EA, Euro Vector, Italy). The root phosphorus content (TP) was quantified using a vanadate-molybdate yellow colorimetric assay after wet digestion with a concentrated H 2 SO 4 -H 2 O 2 mixture 71 . The ratio of root carbon content to root nitrogen content (RCN), the ratio of root carbon content to root phosphorus content (RCP) and the ratio of root nitrogen content to root phosphorus content ratio (RNP) were then calculated. Ten root tips per species were randomly selected from FAA-fixed samples. The tips were dehydrated through an alcohol series and embedded in paraffin. Cross-sections (8 µm thick) were cut at the maturation zone using a microtome 72 , stained with safranine-fast green, and imaged under a compound microscope (Axio Lab, A1 Zeiss). The diameter of first-order roots (FD), epidermal thickness (ET), cortical thickness (CT), and vascular bundle diameter (VBD) were measured using ImageJ software (National Institutes of Health, Bethesda, Maryland, USA). Soil properties analysis Total carbon (TC), nitrogen (TN) and phosphorus (TP) concentrations in the soil were measured in the same way as roots. Carbon content to nitrogen ratio (SCN), carbon content to phosphorus ratio (SCP), and nitrogen content to phosphorus ratio (SNP) were then calculated. Inorganic nitrogen ( \(\:{\text{NO}}_{\text{3}}^{\text{-}}\text{-N}\) and \(\:{\text{NH}}_{\text{4}}^{+}\text{-N}\) ) was extracted with potassium chloride and analyzed using a continuous flow analyzer (Bran and Luebbe, Norderstedt, Germany). Available phosphorus (AP) was determined via dualacid extraction (hydrochloric acid and concentrated sulfuric acid), followed by the molybdenum–antimony colorimetric method 7 3 . Soil pH was measured with a calibrated pH meter (Precision and Scientific Corp, Shanghai, China) in deionized water at a 1:2.5 (w/v) soiltowater ratio. Soil water content was calculated as the mass loss percentage after oven-drying fresh soil at 105°C to constant mass, expressed relative to dry soil mass. Hyphal density (HD, m g − 1 ) in the soil was determined using the modified grid intersect method 74 with a stereo microscope (Leica EZ4W, Leica Microsystems, Germany). Data analysis A two-way ANOVA was conducted using the “car” package to evaluate the effects of microplastic addition, mycorrhizal types and their interactions on soil properties and root traits. The effects of microplastic addition and mycorrhizal types on soil properties and root traits were analyzed using paired sample t -tests in R version 4.1.2 75 . Mantel test analysis was used to explore the relationships between soil properties and root traits for ECM and AM tree species with the “vegan” package. Redundancy analysis (RDA) was used to identify the primary soil factors driving root trait variations for different mycorrhizal types following microplastic addition. Data were standardized prior to analysis using the “vegan” package in R. Principal component analysis (PCA) was performed using R packages “ggplot2” and “vegan” to explore root trait differences in AM and ECM tree species under microplastic addition. Declarations Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Author contributions Yingtong Zhou: Data curation, Writing-Original draft preparation. Ivano Brunner: Writing- Reviewing and Editing. Ziping Liu: Conceptualization, Visualization. Wei Guo: Software, Validation. Xiaoyue Na: Data curation, Formal analysis. Jiaxin Liu: Investigation, Visualization. Junni Wang: Investigation, Methodology. Cunguo Wang: Funding acquisition, Supervision, Writing- Reviewing and Editing. Mai-He Li: Supervision, Writing- Reviewing and Editing. Acknowledgments This work was financially supported by the Natural Science Foundation of China (grant number 42171051). Data availability The data in this study will be submitted to the Dryad Digital Repository once the manuscript is accepted. References Bergmann, M. et al. White and wonderful? Microplastics prevail in snow from the Alps to the Arctic. Science Advances 5, doi:doi: 10.1126/sciadv.aax1157 (2019). Rillig, M. C. Microplastic disguising as soil carbon storage. Environ Sci Technol. 52, 6079–6080, doi: 10.1021/acs.est.8b02338 (2018). Liese, B. et al. Uptake of microplastics and impacts on plant traits of savoy cabbage. Ecotoxicol. Environ. Saf. 272, 116086, doi: 10.1016/j.ecoenv.2024.116086 (2024). Ma, R. et al. Microplastics affect C, N, and P cycling in natural environments: Highlighting the driver of soil hydraulic properties. J. Hazard. Mater. 459, doi: 10.1016/j.jhazmat.2023.132326 (2023). Richard, C. T. et al. Lost at Sea: Where is all the plastic? Science 304, 838, doi: 10.1126/science.1094559 (2004). Li, H. et al. Single and composite damage mechanisms of soil polyethylene/polyvinyl chloride microplastics to the photosynthetic performance of soybean ( Glycine max [L.] merr.). Frontiers in Plant Science 13, doi: 10.3389/fpls.2022.1100291 (2023). Li, R. et al. Visual tracking of label-free microplastics in wheat seedlings and their effects on crop growth and physiology. J. Hazard. Mater. 456, doi: 10.1016/j.jhazmat.2023.131675 (2023). Cayuela, C., Levia, D. F., Latron, J. & Llorens, P. Particulate matter fluxes in a mediterranean mountain forest: interspecific differences between throughfall and stemflow in Oak and Pine stands. Journal of Geophysical Research: Atmospheres 124, 5106–5116, doi: 10.1029/2019jd030276 (2019). Weber, C. J., Rillig, M. C. & Bigalke, M. Mind the gap: forest soils as a hidden hub for global micro- and nanoplastic pollution. Microplastics and Nanoplastics 3, doi: 10.1186/s43591-023-00067-1 (2023). Green, J. K. & Keena, T. F. The limits of forest carbon sequestration. Science 376, 692–693, doi: 10.1126/science.abo6547 (2022). Wang, W. et al. Responses of lettuce ( Lactuca sativa L.) growth and soil properties to conventional non-biodegradable and new biodegradable microplastics. Environ. Pollut. 341, 122897, doi: 10.1016/j.envpol.2023.122897 (2024). Ranauda, M. A. et al. From the rhizosphere to plant fitness: Implications of microplastics soil pollution. Environ. Exp. Bot. 226, 105874, doi: 10.1016/j.envexpbot.2024.105874 (2024). de Souza Machado, A. A., Kloas, W., Zarfl, C., Hempel, S. & Rillig, M. C. Microplastics as an emerging threat to terrestrial ecosystems. Glob Chang Biol. 24, 1405–1416, doi: 10.1111/gcb.14020 (2018). Guerrero-Ramírez, N. et al. Global root traits (GRooT) database. Glob Ecol Biogeogr. 30, 25–37, doi: 10.1111/geb.13179 (2020). Guo, W. et al. Linking fine-root diameter across root orders with climatic, biological and edaphic factors in the Northern Hemisphere. Oikos 2024, doi :/10.1111/oik.10763 (2024). Xu, H. et al. Effects of microplastics concentration on plant root traits and biomass: Experiment and meta-analysis. Ecotoxicol. Environ. Saf. 285, 117038, doi: 10.1016/j.ecoenv.2024.117038 (2024). Sun, H., Lei, C., Xu, J. & Li, R. Foliar uptake and leaf-to-root translocation of nanoplastics with different coating charge in maize plants. J. Hazard. Mater. 416, 125854, doi: 10.1016/j.jhazmat.2021.125854 (2021). Rozman, U. et al. An extensive characterization of various environmentally relevant microplastics – Material properties, leaching and ecotoxicity testing. Sci. Total Environ. 773, 145576, doi: 10.1016/j.scitotenv.2021.145576 (2021). Lehmann, A. et al. Microplastic fiber and drought effects on plants and soil are only slightly modified by arbuscular mycorrhizal fungi. Soil Ecology Letters 4, 32–44, doi: 10.1007/s42832-020-0060-4 (2020). Chen, H. et al. Arbuscular mycorrhizal fungi can inhibit the allocation of microplastics from crop roots to aboveground edible parts. Journal of Agricultural and Food Chemistry 71, 18323–18332, doi: 10.1021/acs.jafc.3c05570 (2023). Urbina, M. A., Correa, F., Aburto, F. & Ferrio, J. P. Adsorption of polyethylene microbeads and physiological effects on hydroponic maize. Sci. Total Environ. 741, 140216, doi: 10.1016/j.scitotenv.2020.140216 (2020). Spanò, C. et al. Polystyrene nanoplastics affect seed germination, cell biology and physiology of rice seedlings in-short term treatments: Evidence of their internalization and translocation. Plant Physiol. Biochem. 172, 158–166, doi: 10.1016/j.plaphy.2022.01.012 (2022). Chen, W. et al. Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees. Proc. Natl. Acad. Sci. 113, 8741–8746, doi: 10.1073/pnas.1601006113 (2016). Kanold, E. P. Microplastic pollution in soil environments: consequences for arbuscular mycorrhizal fungi and plant root traits. University of Guelph (2024). Leifheit, E. F., Lehmann, A. & Rillig, M. C. Potential effects of microplastic on arbuscular mycorrhizal fungi. Front Plant Sci 12, 626709, doi: 10.3389/fpls.2021.626709 (2021). de Souza Machado, A. A. et al. Microplastics can change soil properties and affect plant performance. Environmental Science & Technology 53, 6044–6052, doi: 10.1021/acs.est.9b01339 (2019). Read, D. J. Myeorrhizas in ecosystems. Experientia 47, 376–391, doi: 10.1007/BF01972080 (1991). Chari, N. R., Muratore, T. J. & Taylor, B. N. Long-term soil warming drives different belowground responses in arbuscular mycorrhizal and ectomycorrhizal trees. Global Change Biol. 30, 1–11, doi: 10.1111/gcb.17550 (2024). Pregitzer, K. S. et al. Fine root architecture of nine north American trees. Ecological monographs 72, 293–309 (2002). Terrer, C., Vicca, S., Hungate, B. A., Phillips, R. P. & Prentice, I. C. Mycorrhizal association as a primary control of the CO 2 fertilization effect. Science 353, 72–74, doi: 10.1126/science.aaf4610 (2016). Austen, K., MacLean, J., Balanzategui, D. & Hölker, F. Microplastic inclusion in birch tree roots. Sci. Total Environ. 808, 152085, doi: 10.1016/j.scitotenv.2021.152085 (2022). Midgley, M. G. & Phillips, R. P. Mycorrhizal associations of dominant trees influence nitrate leaching responses to N deposition. Biogeochemistry 117, 241–253, doi: 10.1007/s10533-013-9931-4 (2013). Kuyper, T. W. & Jansa, J. Arbuscular mycorrhiza: advances and retreats in our understanding of the ecological functioning of the mother of all root symbioses. Plant and Soil 489, 41–88, doi: 10.1007/s11104-023-06045-z (2023). Wen, H. et al. Diverse and high pollution of microplastics in seasonal snow across Northeastern China. Sci. Total Environ. 907, 167923, doi: 10.1016/j.scitotenv.2023.167923 (2024). Weber, C., Rillig, M. & Bigalke, M. Mind the gap: forest soils as a hidden hub for global micro- and nanoplastic pollution. Microplast. Nanoplast. 3, 19, doi: 10.1186/s43591-023-00067-1 (2023). Wang, Q. et al. Effects of microplastics and carbon nanotubes on soil geochemical properties and bacterial communities. J. Hazard. Mater. 433, 128826, doi: 10.1016/j.jhazmat.2022.128826 (2022). Read, D. J. Mycorrhizas in ecosystems. Experientia 47, 376–391, doi: 10.1007/BF01972080 (1991). Chari, N. R. et al. Long-term soil warming drives different belowground responses in arbuscular mycorrhizal and ectomycorrhizal trees. Global Change Biol. 30, e17550, doi: 10.1111/gcb.17550 (2024). Dijkstra, F. A., Carrillo, Y., Pendall, E. & Morgan, J. A. Rhizosphere priming: a nutrient perspective. Frontiers in Microbiology 4, doi: 10.3389/fmicb.2013.00216 (2013). Phillips, R. P. & Fahey, T. J. The Influence of Soil Fertility on Rhizosphere Effects in Northern Hardwood Forest Soils. Soil Science Society of America Journal 72, 453–461, doi: 10.2136/sssaj2006.0389 (2008). Zhou, J., Xu, H., Xiang, Y. & Wu, J. Effects of microplastics pollution on plant and soil phosphorus: a meta-analysis. J. Hazard. Mater. 461, 132705, doi: 10.1016/j.jhazmat.2023.132705 (2024). Rillig, M. C., Lehmann, A., de Souza Machado, A. A. & Yang, G. Microplastic effects on plants. New Phytol. 223, 1066–1070, doi: 10.1111/nph.15794 (2019). Gao, B., Yao, H., Li, Y. & Zhu, Y. Microplastic Addition Alters the Microbial Community Structure and Stimulates Soil Carbon Dioxide Emissions in Vegetable-Growing Soil. Environmental Toxicology and Chemistry 40, 352–365, doi: 10.1002/etc.4916 (2021). Qin, W., Hu, C. & Oenema, O. Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat: a meta-analysis. Sci. Rep. 5, 16210, doi: 10.1038/srep16210 (2015). Sajjad, M. et al. Microplastics in the soil environment: A critical review. Environ. Technol. Innovation 27, 102408, doi: 10.1016/j.eti.2022.102408 (2022). Zhang, J. et al. Effects of plastic residues and microplastics on soil ecosystems: A global meta-analysis. J. Hazard. Mater. 435, 129065, doi: 10.1016/j.jhazmat.2022.129065 (2022). Wang, F., Wang, Q., Adams, C. A., Sun, Y. & Zhang, S. Effects of microplastics on soil properties: Current knowledge and future perspectives. J. Hazard. Mater. 424, 127531, doi: 10.1016/j.jhazmat.2021.127531 (2022). Tong, Y. et al. Microplastics affect activity and spatial distribution of C, N, and P hydrolases in rice rhizosphere. Soil Ecology Letters 5, 220138, doi: 10.1007/s42832-022-0138-2 (2022). Yan, Y. et al. Effect of polyvinyl chloride microplastics on bacterial community and nutrient status in two agricultural soils. Bull. Environ. Contam. Toxicol. 107, 602–609, doi: 10.1007/s00128-020-02900-2 (2021). Fei, Y. et al. Response of soil enzyme activities and bacterial communities to the accumulation of microplastics in an acid cropped soil. Sci. Total Environ. 707, 135634, doi: 10.1016/j.scitotenv.2019.135634 (2020). Bosker, T., Bouwman, L. J., Brun, N. R., Behrens, P. & Vijver, M. G. Microplastics accumulate on pores in seed capsule and delay germination and root growth of the terrestrial vascular plant Lepidium sativum . Chemosphere 226, 774–781, doi: 10.1016/j.chemosphere.2019.03.163 (2019). Ceccanti, C. et al. Polyethylene microplastics alter root functionality and affect strawberry plant physiology and fruit quality traits. J. Hazard. Mater. 470, 134164, doi: 10.1016/j.jhazmat.2024.134164 (2024). Liu, Y. et al. Microplastics reduce nitrogen uptake in peanut plants by damaging root cells and impairing soil nitrogen cycling. J. Hazard. Mater. 443, 130384, doi: 10.1016/j.jhazmat.2022.130384 (2023). Leifheit, E. F., Lehmann, A. & Rillig, M. C. Potential effects of microplastic on arbuscular mycorrhizal fungi. Front. Plant Sci. 12, 626709, doi: 10.3389/fpls.2021.626709 (2021). Lian, P., Xu, L., Yang, L., Yue, K. & Peñuelas, J. Divergent soil P accrual in ectomycorrhizal and arbuscular mycorrhizal trees: insights from a common garden experiment in subtropical China. Front. Plant Sci. 15, 1333505, doi: 10.3389/fpls.2024.1333505 (2024). Phillips, R. P., Brzostek, E. & Midgley, M. G. The mycorrhizal-associated nutrient economy: a new framework for predicting carbon–nutrient couplings in temperate forests. New Phytol. 199, 41–51, doi: 10.1111/nph.12221 (2013). Zhu, X. et al. Extraradical hyphae exhibit more plastic nutrient-acquisition strategies than roots under nitrogen enrichment in ectomycorrhiza-dominated forests. Global Change Biol. 29, 4605–4619, doi: 10.1111/gcb.16768 (2023). Finzi, A. et al. Rhizosphere processes are quantitatively important components of terrestrial carbon and nutrient cycles. Global Change Biol. 21, 2082–2094, doi: 10.1111/gcb.12816 (2015). Fort, F. et al. Root traits are related to plant water-use among rangeland Mediterranean species. Functional Ecology 31, 1700–1709, doi: 10.1111/1365-2435.12888 (2017). Bergmann, J. et al. The fungal collaboration gradient dominates the root economics space in plants. Science Advances 6, eaba3756, doi: 10.1126/sciadv.aba3756 (2020). Geng, P. & Jin, G. Fine root morphology and chemical responses to N addition depend on root function and soil depth in a Korean pine plantation in Northeast China. Forest Ecology and Management 520, doi: 10.1016/j.foreco.2022.120407 (2022). Jonathan, A. B. et al. Plant-soil feedbacks and mycorrhizal type influence temperate forest population dynamics. Science 355, 181–184, doi: 10.1126/science.aai8212 (2017). Fahey, C., Bell, F. W. & Antunes, P. M. Effects of dual mycorrhizal inoculation on Pinus strobus seedlings are influenced by soil resource availability. Plant and Soil 479, 607–620, doi: 10.1007/s11104-022-05546-7 (2022). Tisserant, E. et al. Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis. Proceedings of the National Academy of Sciences 110, 20117–20122, doi: 10.1073/pnas.1313452110 (2013). Mathur, S., Tomar, R. S. & Jajoo, A. Arbuscular mycorrhizal fungi (AMF) protects photosynthetic apparatus of wheat under drought stress. Photosynth Res 139, 227–238, doi: 10.1007/s11120-018-0538-4 (2019). Xie, K. et al. Plant nitrogen nutrition: The roles of arbuscular mycorrhizal fungi. J. Plant Physiol. 269, 153591, doi: 10.1016/j.jplph.2021.153591 (2022). Smith, S. E., Smith, F. A. & Jakobsen, I. Functional diversity in arbuscular mycorrhizal (AM) symbioses: the contribution of the mycorrhizal P uptake pathway is not correlated with mycorrhizal responses in growth or total P uptake. New Phytol. 162, 511–524, doi: 10.1111/j.1469-8137.2004.01039.x (2004). Jing, M., Shi, Z., Zhang, M., Zhang, M. & Wang, X. Nitrogen and Phosphorus of Plants Associated with Arbuscular and Ectomycorrhizas Are Differentially Influenced by Drought. Plants 11, doi: 10.3390/plants11182429 (2022). Fu, W. et al. Community response of arbuscular mycorrhizal fungi to extreme drought in a cold-temperate grassland. New Phytol 234, 2003–2017, doi: 10.1111/nph.17692 (2022). Comas, L. H. & Eissenstat, D. M. Linking fine root traits to maximum potential growth rate among 11 mature temperate tree species. Functional Ecology 18, 388–397, doi: 10.1111/j.0269-8463.2004.00835.x (2004). Lu Ru, k. Analytical methods for soil and agriculture chemitry. , Vol. 4 312–314 (China Agricultural Science and Technology Press, 2000). Gu, J., Xu, Y., Dong, X., Wang, H. & Wang, Z. Root diameter variations explained by anatomy and phylogeny of 50 tropical and temperate tree species. Tree Physiol 34, 415–425, doi: 10.1093/treephys/tpu019 (2014). Mehlich, A. Mehlich 3 soil test extractant: A modification of Mehlich 2 extractant. Communications in Soil Science and Plant Analysis 15, 1409–1416, doi: 10.1080/00103628409367568 (2008). Brundrett, M. Practical methods in mycorrhiza research: based on a workshop organized in conjunction with the ninth North American Conference on mycorrhizae, University of Guelph, Guelph, Ontario, Canada., (1994). R: A language and environment for statistical computing (R Foundation for Statistical Computing, 2021). Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 27 Jan, 2026 Read the published version in Communications Earth & Environment → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6627952","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":458477219,"identity":"d43b3c65-c641-453c-97b4-c362241cbbac","order_by":0,"name":"Cunguo Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIiWNgGAWjYPCCfzz27Q1Q9gHitByQM+CBKSVWi7GBRAKRWgyOnz384sevO4nbJd8efFzYxiDHdyOB8XMBPi1n8tIse/ueJe6cnZdsPLONwVjyRgKz9Aw8WswO5JgZM/YwJzbczjGT5m1jSNxwI4GNmQeflvNvoFpunjH/DdRST1jLjRzjxww/Dhsb3OAxYwZqSTAgpMX+xhszxt6GNDnJnhxjaZ5zEoYzzzxslsanRbI/x/jDjz82PPzsZww/85TZyPMdTz74GZ8WIGCTYGyDcySAmLEBvwYGBuYPDH8IqRkFo2AUjIIRDQCOSlBJs6LD2AAAAABJRU5ErkJggg==","orcid":"","institution":"Northeast Normal University","correspondingAuthor":true,"prefix":"","firstName":"Cunguo","middleName":"","lastName":"Wang","suffix":""},{"id":458477220,"identity":"0290c6d9-bfc3-4d52-9dba-95fb41b0ba60","order_by":1,"name":"Yingtong Zhou","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yingtong","middleName":"","lastName":"Zhou","suffix":""},{"id":458477221,"identity":"07277610-a436-435b-9a98-487c6ae7ceba","order_by":2,"name":"Ivano Brunner","email":"","orcid":"https://orcid.org/0000-0003-3436-995X","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Ivano","middleName":"","lastName":"Brunner","suffix":""},{"id":458477222,"identity":"ac367513-828b-47dc-b5fa-d45b3fa6a7ca","order_by":3,"name":"Ziping Liu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Ziping","middleName":"","lastName":"Liu","suffix":""},{"id":458477223,"identity":"55c2e3eb-affa-485c-8a9b-092369184370","order_by":4,"name":"Wei Guo","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Guo","suffix":""},{"id":458477224,"identity":"0dfdb465-f6e5-4dd5-a9a4-2e0be07f2d49","order_by":5,"name":"Xiaoyue Na","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Xiaoyue","middleName":"","lastName":"Na","suffix":""},{"id":458477225,"identity":"786e73ba-b7f5-4ab6-a008-9d32dc8fbe08","order_by":6,"name":"Jiaxin Liu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Jiaxin","middleName":"","lastName":"Liu","suffix":""},{"id":458477226,"identity":"3e042145-bbfa-4023-81fe-27e732e557c0","order_by":7,"name":"Junni Wang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Junni","middleName":"","lastName":"Wang","suffix":""},{"id":458477227,"identity":"66c215af-6f09-4e4f-8308-ac4a4924bc41","order_by":8,"name":"Mai-He Li","email":"","orcid":"https://orcid.org/0000-0002-7029-2841","institution":"Forest dynamics, Swiss Federal Research Institute WSL","correspondingAuthor":false,"prefix":"","firstName":"Mai-He","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2025-05-09 11:11:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6627952/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6627952/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s43247-026-03237-0","type":"published","date":"2026-01-27T05:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83352119,"identity":"44cb4d42-31ec-46a8-a878-00cbd3ab5d66","added_by":"auto","created_at":"2025-05-23 14:21:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":105134,"visible":true,"origin":"","legend":"\u003cp\u003eSoil properties of ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species under control (CK) and microplastic addition (MP). Asterisks indicate significant differences between CK and MP for ECM and AM tree species, respectively. \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001; \u003csup\u003e**\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01; \u003csup\u003e*\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05 and ns, not significant. The abbreviations are defined in Table 1.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/03296b40d07d8dc31fd02850.png"},{"id":83353160,"identity":"615a4331-03c7-4711-8c14-c0cf7cde5ad3","added_by":"auto","created_at":"2025-05-23 14:29:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":55419,"visible":true,"origin":"","legend":"\u003cp\u003eRoot chemical traits of ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species under control (CK) and microplastic addition (MP). Asterisks indicate significant differences between CK and MP for ECM and AM tree species, respectively. \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001; \u003csup\u003e**\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01; \u003csup\u003e*\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05 and ns, not significant. The abbreviations are defined in Table 2.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/56d7fd61be411b8d35fc08e6.png"},{"id":83351755,"identity":"2043689c-4ddd-4916-bc26-4f9415741252","added_by":"auto","created_at":"2025-05-23 14:13:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":103467,"visible":true,"origin":"","legend":"\u003cp\u003eRoot morphological and anatomical traits of ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species under control (CK) and microplastic addition (MP). Asterisks indicate significant differences between CK and MP for ECM and AM tree species, respectively. \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001; \u003csup\u003e**\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01; \u003csup\u003e*\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05 and ns, not significant. The abbreviations are defined in Table 2.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/0e2ca5b56c9c0423c582f7c8.png"},{"id":83353516,"identity":"48c5b7ee-52e9-4353-aae0-e7f3dc903df2","added_by":"auto","created_at":"2025-05-23 14:37:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":228671,"visible":true,"origin":"","legend":"\u003cp\u003eMantel test analysis of soil properties with root chemical traits, root anatomical traits, root morphological traits and hyphal density of ectomycorrhizal (ECM, a) and arbuscular mycorrhizal (AM, b) tree species. The abbreviations of soil properties are defined in Table 1. HD, hyphal density. \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001, \u003csup\u003e**\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01 and \u003csup\u003e*\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/7460551b04b9358c6b8287f1.png"},{"id":83351762,"identity":"88481845-cad7-4c2b-9f55-6355d2bcf919","added_by":"auto","created_at":"2025-05-23 14:13:00","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":103009,"visible":true,"origin":"","legend":"\u003cp\u003eRedundancy analysis (RDA) of root traits and soil properties for ectomycorrhizal (ECM, a) and arbuscular mycorrhizal (AM, b) tree species under control (CK) and microplastic addition (MP). The abbreviations of soil properties and root traits are defined in Tables 1, 2. Red arrows indicate soil properties with \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/e111305c73ee0ea12da15e27.png"},{"id":83352121,"identity":"9e00a3cf-6d3c-4c74-88e7-cf5a5dcccbd2","added_by":"auto","created_at":"2025-05-23 14:21:00","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":72030,"visible":true,"origin":"","legend":"\u003cp\u003eScatter plots (a, b) of principal component analysis (PCA) on root traits and the scores of first (c) and second (d) principal components for ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species under control (CK) and microplastic addition (MP). Asterisks indicate significant differences between CK and MP for ECM and AM tree species, respectively. \u003csup\u003e\u003cem\u003e***\u003c/em\u003e\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001 and \u003csup\u003e**\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01. The abbreviations of root traits are defined in Table 2. The confidence ellipses of 95% are given for ECM and AM tree species.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/458691f6630b7d673e03af84.png"},{"id":83352128,"identity":"d49dba9a-0b2b-45ac-88a3-89208abdb016","added_by":"auto","created_at":"2025-05-23 14:21:00","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":3943842,"visible":true,"origin":"","legend":"\u003cp\u003eConceptual graphic illustrating the influences of microplastics on soil and fine roots for ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/da709e4c798c9e80c93844ac.png"},{"id":103637731,"identity":"0e583076-2f7e-4731-8d43-2939da0244c8","added_by":"auto","created_at":"2026-02-28 08:13:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5176781,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6627952/v1/e3ccf774-9cce-4154-a563-da4e5960de06.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Mycorrhizal-specific responses of rhizosphere soil properties and fine-root traits to polystyrene microplastic addition in a temperate mixed forest","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMicroplastics, defined as plastic particles smaller than 5 mm in diameter, are formed by plastic polymers under the influence of light, mechanical abrasion and temperature fluctuations \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. While the effects of microplastics on aquatic ecosystems are well studied, the effects on terrestrial ecosystems, especially on plants, are only gradually being researched \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Microplastics, which are known for their corrosion resistance, are widely distributed in terrestrial ecosystems, including forest soils, and remain in the environment for long periods of time \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Forests can effectively filter atmospheric microplastics, with intercepted particles accumulating in organic layers of forest soils before leaching into mineral soils \u003csup\u003e\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Microplastics impair the cohesion between soil aggregates, which in turn alters physical properties such as water retention capacity and bulk density, the availability of nutrients in the soil and their uptake by plants, and increases oxidative stress, which ultimately induces toxicity that affects photosynthesis and plant growth \u003csup\u003e\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The ability of trees to acquire soil nutrients under microplastic accumulation will influence forest composition and function in a changing world.\u003c/p\u003e \u003cp\u003eIn general, the efficiency of resource acquisition by trees is optimized by the plasticity of root morphology (e.g., root length) and anatomy (e.g., cortical thickness) in forest ecosystems \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. A recent meta-analysis indicated that microplastics can reduce root biomass and root length \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. The negative effects of microplastic on roots can be that it blocks the cell junctions or the cell wall, mechanically damages the roots and leads to a decrease in root activity and hinders the general growth of the roots \u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. The metabolic costs of fine roots (fine root respiration) are major factors that prevents plants from efficiently exploring the soil and absorbing nutrients under unfavorable conditions \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Thus, increasing the stele diameter of roots (which have a lower metabolic rate) and/or the reducing the cortical thickness of roots (which have a higher metabolic rate) can reduce fine root respiration and nutrient demand (e.g., lower root nitrogen concentration) and thus increase the resource acquisition efficiency of plants in microplastic-polluted soils \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIt is concluded that root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees \u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Although arbuscular mycorrhizal (AM) fungi cannot reduce the absorption of microplastics by plants, they can immobilize microplastics in vesicles and hyphae, and enhance the resistance of plants to microplastics by altering the chemical characteristics of microplastics, such as reducing their complexation \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Thus, tree associations with AM fungi may be able to alleviate the direct stress associated with the addition of microplastic in soil \u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. The altered habitat caused by the addition of polyester microplastic led to the colonization of the roots by AM fungi, which conferred positive effects on plant growth by increasing nutrient availability \u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Moreover, it is noted that ectomycorrhizal (ECM) fungi have the ability to mobilize nutrients from organic forms \u003csup\u003e\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. Thus, we speculate that roots of trees associated with ECM fungi can overcome nitrogen and phosphorus limitation induced by microplastic accumulations in soils \u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. However, interactions of microplastics with roots of ECM trees have been not understood in temperate forest ecosystems \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. Given the contrasting roles of AM and ECM fungi on carbon and nutrient cycles \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e, the unresolved mechanisms underlying AM and ECM tree responses to microplastics strongly restrict our understanding of how trees shift their allocation of resources to different nutrient acquisition strategies under increasing microplastic deposition in forest ecosystems \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eA recent study has indicated that the Changbai mountains have the highest deposition of microplastics in seasonal snow in north-east China \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e. Here, we quantified the microplastic-induced alterations in soil properties in the rhizosphere and the morphological, chemical and anatomical adaptations of fine roots between AM and ECM tree species after the addition of microplastics in a mixed \u003cem\u003ePinus koraiensis\u003c/em\u003e forest in the Changbai mountains. We hypothesize that (1) the negative impacts of microplastic addition on soil properties are specific to mycorrhizal associations, and that (2) the two mycorrhizal tree species (AM \u003cem\u003eversus\u003c/em\u003e ECM) would show different strategies for the acquisition of root resources under microplastic addition. In particular, AM tree species would pursue a more proactive root exploration strategy compared to ECM tree species, which would demonstrate enhanced mycorrhizal symbiosis for resource acquisition under microplastic addition.\u003c/p\u003e"},{"header":"Result","content":"\u003cp\u003eWe found that mycorrhizal type, microplastic addition and their interactions significantly affected most of soil properties, expect for SCN (for mycorrhizal type),\u0026nbsp;\u0026nbsp;\u0026nbsp;(for microplastic addition) and pH (for mycorrhizal type and microplastic addition), as well as TP and SCN (for the interactions of mycorrhizal type and microplastic addition; Table 1). Specifically, microplastic addition significantly increased TC, TN, AN,\u0026nbsp;\u0026nbsp;,\u0026nbsp;\u0026nbsp;\u0026nbsp;and SWC of ECM tree species, but decreased the corresponding properties of AM tree species (Figure 1). ECM tree species significantly decreased TP, leading to increases in SCP and SNP under microplastic addition (Figure 1c, e, f). Soil pH and AP of ECM tree species significantly decreased, but those of AM tree species increased following microplastic addition (Figure 1j, k).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe observed that mycorrhizal type significantly affected RC, RN, RP, RCN, RCP, RNP, RTD, TD and HD, while microplastic addition significantly affected RC, RN, RCN, RCP, RL, BI and HD. Meanwhile, RC, RP, RCP, BR and HD were significantly influenced by the interactions of mycorrhizal type and microplastic addition (Table 2). Specifically, RC and RCN of both ECM and AM tree species were significantly higher in microplastic addition treatment than in CK (Figure 2a, d). RN of AM tree species significantly decreased, while RP of ECM tree species significantly decreased under microplastic addition (Figure 2b, c). Microplastic addition significantly increased RCP of ECM tree species but decreased RNP of AM tree species (Figure 2e, f). Microplastic addition significantly decreased RL, RD, RTD, BR, BI and FD of ECM tree species, while increased HD. Conversely, AM tree species significantly increased SRL, TD, ET and VBD, but decreased RTD, BI, FD and CT following microplastic addition (Figure 3).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMantel test analysis showed that morphological, chemical and anatomical traits of fine roots, as well as hyphal density for ECM tree species were more associated with soil properties than AM tree species. Root anatomy and morphology of ECM tree species was related to TP, pH and \u0026nbsp;, while that of AM tree species was related to AP, \u0026nbsp; and \u0026nbsp; (Figure 4). Furthermore, redundancy analysis showed that TP, as well as \u0026nbsp;, SWC and AP were the strongest determinant of root traits in ECM and AM tree species, respectively (Figure 5). Principal component analysis showed that the first two principal components explained 59.3% of the variance in root traits (Figure 6a). Root anatomical and morphological traits (expect for RTD) mainly loaded on the first principal component, while root chemical traits and RTD on the second principal component (Figure 6a). ECM and AM tree species were clearly differentiated by the second principal component (Fig. 6b), which was confirmed by differences in the scores along the first and second principal components between ECM and AM tree species (Figure 6c, d).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e. Effects of mycorrhizal type (MT), microplastic addition (MP) and their interactions (MT \u0026times; MP) on soil properties using two-way ANOVAs. \u003cem\u003eF\u003c/em\u003e values are given.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"931\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eFactors\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 31px;\"\u003e\n \u003cp\u003edf\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eTC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003eTN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003eTP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eSCN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eSCP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eSNP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003eAN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eAP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003epH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003eSWC\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eMT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 31px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e235\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e306\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e13.7\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e10.6\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e21.9\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e16.4\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e52.1\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e122\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e91.9\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e326\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eMP\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 31px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e26.1\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e12.4\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e12.3\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e36.9\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e18.4\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e20.2\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.38\u003c/strong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e10.3\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e59.0\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e154\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eMT \u0026times; MP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 31px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e254\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e347\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003e2.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e35.2\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e49.4\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e29.8\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e29.2\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e145\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e112\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e24.7\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e296\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eResiduals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 31px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003edf, degree of freedom; TC, soil total carbon concentration (g kg\u003csup\u003e-1\u003c/sup\u003e); TN, soil total nitrogen concentration (g kg\u003csup\u003e-1\u003c/sup\u003e); TP, soil total phosphorus concentration (g kg\u003csup\u003e-1\u003c/sup\u003e); SCN, the ratio of soil total carbon concentration to soil total nitrogen concentration; SCP, the ratio of soil total carbon concentration to soil total phosphorus concentration; SNP, the ratio of soil total nitrogen concentration to soil total phosphorus concentration; \u0026nbsp;, soil nitrate nitrogen concentration (mg kg\u003csup\u003e-1\u003c/sup\u003e); \u0026nbsp;, soil ammonium nitrogen concentration (mg kg\u003csup\u003e-1\u003c/sup\u003e); AN, soil available nitrogen concentration (mg kg\u003csup\u003e-1\u003c/sup\u003e); AP, soil available phosphorus concentration (mg kg\u003csup\u003e-1\u003c/sup\u003e); pH, soil pH; SWC, soil water content (%). \u003cstrong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001; \u003cstrong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01; \u003cstrong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05. Significant \u003cem\u003eP\u003c/em\u003e-values (\u0026lt;0.05) are in bold.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e. Effects of mycorrhizal type (MT), microplastic addition (MP) and their interactions (MT \u0026times; MP) on chemical, morphological and anatomical traits of fine roots, as well as hyphal trait using two-way ANOVAs. \u003cem\u003eF\u003c/em\u003e values are given.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"1134\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" style=\"width: 343px;\"\u003e\n \u003cp\u003eChemical traits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"7\" style=\"width: 361px;\"\u003e\n \u003cp\u003eMorphological traits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eHyphal trait\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" style=\"width: 192px;\"\u003e\n \u003cp\u003eAnatomical traits\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003eFactor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003edf\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 59px;\"\u003e\n \u003cp\u003eRC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003eRN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003eRP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003eRCN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003eRCP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003eRNP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003eRL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003eRD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003eSRL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003eRTD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003eBR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003eBI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003eTD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eHD\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e8.61\u003csup\u003e**\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e21.0\u003csup\u003e***\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e8.73\u003csup\u003e**\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003eFD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003eET\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003eVBD\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003eMT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e30.0\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e46.7\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e12.1\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e29.6\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e36.8\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e100\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e1.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e2.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5.56\u003c/strong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e3.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.18\u003csup\u003e*\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003eMP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e46.3\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.67\u003c/strong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e24.2\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e15.7\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e1.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5.46\u003c/strong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003e3.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e2.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e8.14\u003csup\u003e**\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e1.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003eMT \u0026times; MP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e25.2\u003c/strong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e1.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.62\u003c/strong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e9.00\u003c/strong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e3 .34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5.78\u003csup\u003e*\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003eResiduals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 33px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 59px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003e0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003edf, degree of freedom; RC, root carbon concentration (%); RN, root nitrogen concentration (g kg\u003csup\u003e-1\u003c/sup\u003e); RP, root phosphorus concentration (g kg\u003csup\u003e-1\u003c/sup\u003e); RCN, root carbon concentration to root nitrogen concentration; RCP, root carbon concentration to root phosphorus concentration; RNP, root nitrogen concentration to root phosphorus concentration. RL, root length (cm cm\u003csup\u003e-3\u003c/sup\u003e); RD, root diameter (mm); SRL, specific root length (cm g\u003csup\u003e-1\u003c/sup\u003e); RTD, root tissue density (g cm\u003csup\u003e-3\u003c/sup\u003e); BR, branching ratio; BI, branching intensity (no cm\u003csup\u003e-1\u003c/sup\u003e); TD, tip density (no cm\u003csup\u003e-3\u003c/sup\u003e); HD, hyphal density (m g\u003csup\u003e-1\u003c/sup\u003e); FD, the diameter of first-order roots (mm); ET, epidermal thickness (mm); CT, cortical thickness (mm); VBD, vascular bundle diameter (mm). \u003cstrong\u003e\u003csup\u003e***\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001; \u003cstrong\u003e\u003csup\u003e**\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01; \u003cstrong\u003e\u003csup\u003e*\u003c/sup\u003e\u003c/strong\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05. Significant \u003cem\u003eP\u003c/em\u003e-values (\u0026lt;0.05) are in bold.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eImpacts of microplastics on soil properties of ECM and AM tree species\u003c/h2\u003e \u003cp\u003eWe found that rhizosphere soil of ECM tree species significantly increased nitrogen availability, but decreased phosphorus availability following microplastic addition (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The accumulation of inorganic nitrogen such as nitrate and ammonium nitrogen are dependent of its balance between production (e.g. nitrification and mineralization) and depletion (e.g. denitrification and microbial immobilization) \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. It is widely accepted that ECM fungi have the ability to obtain nitrogen from organic forms \u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e,\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. We expected that microplastic accumulation in soils appears to amplify the ECM symbiotic nitrification and nitrogen mineralization efficiency, resulting in increased concentrations of nitrate and ammonium nitrogen in the rhizosphere soil of ECM tree species \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e,\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. However, the available phosphorus of ECM tree species was found to be lower after the addition of microplastics in the mixed forest, partially supporting our first hypothesis, which is consistent with a recent meta-analysis \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. These findings potentially suggest the negative effects of microplastics on phosphorus mineralization of ECM fungi by reducing phosphatase activity \u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e,\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. Furthermore, microplastic addition significantly increased soil water content of ECM tree species, which is due to the fact that microplastics can be an obstacle to evaporation and can change soil bulk density \u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. At the same time, we observed that soil water content was negatively related to the available phosphorus of ECM tree species (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea), confirming the statement that microplastics are likely to exacerbate soil phosphorus leaching \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e,\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e,\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e. This is also supported by the lower soil total phosphorus of ECM tree species (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eCompared to the ECM tree species, we found lower available nitrogen, especially nitrate nitrogen, but higher available phosphorus in the rhizosphere soil of the AM tree species under microplastic addition in the mixed forest, which supports our first hypothesis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Our results of the negative effects of microplastic on nitrate nitrogen are in accordance with previous findings \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. We observed that AM tree species significantly increased the ratio between soil total carbon concentration and soil total nitrogen concentration after the addition of microplastics, while ECM tree species did not (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The higher carbon to nitrogen ratio caused by microplastics may enhance nitrogen immobilization by microbes, leading to the decreased inorganic nitrogen accumulation in rhizosphere soil of AM tree species \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. These findings are also supported by the significantly negative relationships of the carbon to nitrogen ratio and the available (ammonium) nitrogen (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). Furthermore, we speculate that the addition of microplastics may reduce the relative abundance of nitrifiers involved in nitrification, which partly explains the lower soil nitrate nitrogen and higher soil pH of AM tree species (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), as the nitrification process leads to a low soil pH \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. It is indicated that AM fungi enhance the resistance of plants to microplastics through transforming the chemical properties of microplastics, and promoting phosphorus nutrition at high microplastic addition levels \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Microplastic addition may possibly lead to phosphorus mobilization from inorganic and organic sources \u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. The increase of phosphatase activity under exposure to microplastics promotes the decomposition and transformation of organophosphorus compounds, leading to a significant increase in soil inorganic phosphorus \u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e,\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e. In summary, our findings suggest that the effects of microplastic pollution on soil nutrients in forest ecosystems may be mycorrhiza-specific, although the underlying mechanisms are not yet fully understood (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eImpacts of microplastics on root traits of ECM and AM tree species\u003c/h3\u003e\n\u003cp\u003eIn this study, we observed the consistent responses of root chemical traits to microplastic addition for ECM and AM tree species, with the higher root carbon to nitrogen ratio, as well as root phosphorus or root nitrogen concentration (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Our findings indicate that microplastics have a detrimental effect on root nutrient contents, although more available nitrogen and phosphorus were found in the rhizosphere soil of ECM and AM tree species, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Microplastics that adhere to fine roots can clog pores and channels and thus impair root growth \u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e,\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e. Indeed, microplastics have negative impacts on root tissues and directly damage the morphology of root cells, which further reduces the nutrient uptake of plant roots \u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. This assertion is supported by our findings that the diameter of first-order roots and the density of root tissue of the entire root system is lower in ECM and AM tree species under microplastic addition (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). In combination with a reduced soil bulk density through microplastic addition it can be expected that fine roots experience a reduced penetration resistance, thus decreasing the diameter of fine roots \u003csup\u003e\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e. However, the lower diameter and root tissue density indicate that root lifespans are shorter, reflecting the microplastic accumulation in soils potentially enhances the carbon input from plants into the soil through root turnover in forest ecosystems.\u003c/p\u003e \u003cp\u003eOur results provide evidence that trees differentially modify their root morphological traits under microplastic addition depending on their dominant mycorrhizal associations, which is in line with our second hypothesis. Generally, mycorrhizal symbiosis (allocating carbon to mycorrhizal fungi) and root exploration (allocating carbon to fine root system expansion) are considered as two root nutrient acquisition strategies that trees use to forage for soil resources \u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. Overall, it can be observed that ECM tree species produce root systems with shorter root length, lower branching ratio and lower branching intensity, but denser hyphae under microplastic accumulation in soils (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), indicating a switch in the nutrient acquisition mechanism from root exploration to mycorrhizal symbiosis. We speculate that the increased carbon allocation to mycorrhizas by ECM tree species under microplastic addition is related to the ability of ECM fungi to mobilise organic nutrient \u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e,\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. This indicates that ECM trees may enhance their response to external environmental stress by enhancing the extent of mycorrhizal hyphae in unfavorable soil environments \u003csup\u003e\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e,\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e\u003c/sup\u003e. Therefore, ECM tree species may rely on mycorrhizal associations with their roots to acquire soil nutrients, specifically for phosphorus in microplastic polluted soils in forest ecosystems (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWe observed different responses to the addition of microplastics in AM tree species, where specific root length and tip density increased, whereas in ECM tree species these parameters did not change (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which may suggest that AM tree species adopt a root-dependent strategy under microplastic accumulation in soils in forest ecosystems. Higher specific root length can facilitate rapid nutrient foraging (specifically for inorganic nitrogen) at lower carbon costs \u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e,\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e. Meanwhile, cortical thickness of roots of AM tree species decreased under microplastic addition, while that for ECM tree species did not (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), indicating a reduced mycorrhizal colonization potential of AM tree species. These findings provide evidence that carbon allocation to mycorrhizal fungi may be downregulated by AM tree species under microplastic accumulation in soils. Concurrently, AM tree species exhibit synchronized increases in epidermal thickness and vascular bundle diameter under microplastic addition. The thickened epidermis may reduce mechanical damage caused by microplastics, while the enlarged vascular bundle diameter can offset hydraulic losses resulting from decreased root tissue density \u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e. Thus, AM tree species invested more in the absorption and transport capacity of their own root system and in defense mechanisms than in symbiotic strategies associated with the absorptive roots of ECM tree species (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003eRegulation of the responses of root traits to microplastic addition for ECM and AM tree species\u003c/b\u003e \u003c/p\u003e \u003cp\u003eBoth the mantel test analysis and the principal component analysis demonstrated significant differences in the associations of morphological, chemical and anatomical root traits to soil properties between ECM and AM tree species under microplastic addition (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Furthermore, redundancy analysis showed that soil total phosphorus, as well as nitrate nitrogen, available phosphorus and soil water content emerged as key constraints on root traits of ECM and AM tree species, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). As mentioned above, microplastic addition results in declines in total and available phosphorus in rhizosphere soil of ECM tree species, thereby limiting root phosphorus absorption \u003csup\u003e\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e,\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e. This is confirmed by the lower root phosphorus concentration of ECM tree species (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In contrast, AM tree species may experience greater nitrogen limitation in microplastic polluted environments due to their greater reliance on unstable soluble nitrogen pools and lack in saprotrophic capacity to access complex organic nitrogen compared with ECM tree species \u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e,\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e. Reduced root nitrogen coupled with stable root phosphorus increase root nitrogen to phosphorus ratio, indicating faster nitrogen loss rate than phosphorus of AM tree species \u003csup\u003e\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e\u003c/sup\u003e. Indeed, it has been repeatedly demonstrated that AM fungi can dominate phosphorus uptake in symbiotic plants, and in several plant-AM fungus associations, a nearly 100% contribution of the mycorrhizal pathway to the overall phosphorus uptake was estimated \u003csup\u003e\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e,\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e\u003c/sup\u003e. Moreover, AM tree species are more sensitive to drought stress than that of ECM \u003csup\u003e\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e,\u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e69\u003c/span\u003e\u003c/sup\u003e. Thus, microplastic-induced declines in soil water content can exacerbate AM fungal vulnerability, as hydraulic efficiency governs the performance of the symbiosis under drought conditions \u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e,\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e\u003c/sup\u003e. In summary, these findings highlight the different role of soil properties in regulating root adaptations to microplastic accumulation in soils of different mycorrhizal types in this mixed forest.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study suggests that the addition of microplastics affects the soil properties of the rhizosphere of ECM and AM tree species in the mixed forest in Changbai mountains differently. The nitrogen availability of the rhizosphere soil increased significantly, but the phosphorus availability decreased after the addition of microplastics in ECM tree species. In contrast, AM tree species showed an opposite response pattern to the addition of microplastics, with a lower concentration of available nitrogen but a higher concentration of available phosphorus in the rhizosphere soil. Together with the results of root chemical trait responses to microplastic addition, our findings indicate that microplastics were detrimental to nitrogen and phosphorus uptake by roots of ECM and AM tree species in forest ecosystems. Moreover, ECM tree species tended to produce root systems with lower root length, root diameter, root tissue density, branching ratio, branching intensity but higher hyphal density under microplastic accumulation in soils, while AM tree species tended to produce root systems with higher specific root length, tip density, epidermal thickness and vascular bundle diameter, but branching intensity, cortical thickness and root tissue density. Accordingly, our results provide evidence that ECM and AM tree species exhibited two divergent nutrient acquisition strategies, mediated by soil total phosphorus, as well as by soil water content, nitrate nitrogen and available phosphorus, respectively. Overall, these findings highlight that microplastic pollution disrupts nutrient acquisition pathways differently in ECM and AM trees, which has a strong impact on carbon and nutrient cycling, as well as on the dynamics of tree species composition in temperate mixed forest ecosystems.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStudy site\u003c/h2\u003e \u003cp\u003eThe study site (42\u0026deg;24\u0026prime;N, 127\u0026deg;47\u0026prime;E, 738 m above sea level) is located in a mixed mature \u003cem\u003eP. koraiensis\u003c/em\u003e forest within the Changbai Mountain Nature Reserve in Jilin province, China. In this region, the mean annual air temperature is 3.5\u0026deg;C, and the highest and lowest monthly mean air temperatures appear in August (20.5\u0026deg;C) and January (\u0026minus;\u0026thinsp;16.5\u0026deg;C), respectively. The mean annual precipitation is 740 mm. The soil has developed from volcanic ash and is classified as Eutric cambisol with a high organic matter content in the surface layer. The mixed mature forest is dominated by the coniferous species \u003cem\u003eP. koraiensis\u003c/em\u003e and broad-leaved tree species such as \u003cem\u003eTilia amurensis\u003c/em\u003e, \u003cem\u003eFraxinus mandshurica\u003c/em\u003e, \u003cem\u003ePhellodendron amurense\u003c/em\u003e, \u003cem\u003eJuglans mandshurica\u003c/em\u003e and \u003cem\u003eAcer mono\u003c/em\u003e. This forest exhibits a complex multi-layered structure and represents the typical zonal climax vegetation of the humid mountain areas in northeastern China. In this study, the four tree species \u003cem\u003eP. koraiensis\u003c/em\u003e (ECM), \u003cem\u003eT. amurensis\u003c/em\u003e (ECM), \u003cem\u003eP. amurense\u003c/em\u003e (AM), and \u003cem\u003eJ. mandshurica\u003c/em\u003e (AM) were selected to investigate the responses of rhizosphere soil properties and root traits of different mycorrhizal types to the addition of microplastics.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eExperimental design\u003c/h3\u003e\n\u003cp\u003eIn this study, we used the root bag method \u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e\u003c/sup\u003e to isolate roots of different tree species in the mixed forest. In early May 2023, woody coarse roots (25 cm long, ~\u0026thinsp;5 mm in diameter) were excavated from selected trees without cutting them off. All fine and lateral roots were then removed at the distal end before the trimmed roots were placed into polyester root bags (30\u0026times;30 cm, 0.5 mm mesh). To obtain 1% (w/w) microplastic treated soil, we previously mixed 1.25 kg of polystyrene particles (100 \u0026micro;m in diameter; Dongguan Xinchangqiao Plastic Co., Ltd., China) thoroughly with 125 kg of soil (sieved fresh soil collected from the 0\u0026ndash;20 cm forest floor layer). A total of 48 polystyrene-treated root bags (microplastic addition \u0026ldquo;MP\u0026rdquo;, 2.5 kg of polystyrene treated soil) were prepared (4 bags per tree individual \u0026times; 3 individuals per tree species \u0026times; 4 tree species), while the control bags (\u0026ldquo;CK\u0026rdquo;, 48 bags) were filled with soil in the same manner but without the addition of polystyrene particles. The root bags were then reburied in the original forest soil, covered with the pre-existing leaf litter layer, and wetted with water.\u003c/p\u003e \u003cp\u003eIn late September 2023, we retrieved the root bags by cutting the woody roots at the bag entrance. The collected bags were immediately stored in a refrigerated container and transported to the laboratory. Root samples were carefully removed from each root bag, and rhizosphere soil was collected by gently shaking off adhering soil. For anatomical analysis, the root samples with intact fine root branches were fixed in a formalin-acetic acid-ethanol solution (90 ml of 70% ethanol, 5 ml of 100% glacial acetic acid, 5 ml of 38% formaldehyde). The root and soil samples were kept under cold conditions at 4\u0026deg;C for subsequent analyses.\u003c/p\u003e\n\u003ch3\u003eRoot trait measurements\u003c/h3\u003e\n\u003cp\u003eAfter cleaning the root surfaces, we scanned the samples into image files using an Epson Perfection V700 root scanner (1200 dpi resolution). The images were then analyzed using root analysis software (WinRhizo, Regent Instruments Inc., Quebec, Canada) to determine average root diameter (RD), average root volume and root length (RL). Branching ratio (BR) was defined as the number of first-order roots divided by the number of second-order roots. Branching intensity (BI) was calculated as the number of first-order roots per unit length (cm) of second-order roots. Root tip density (TD) was quantified as the number of root tips per unit volume (cm\u0026sup3;) of soil. The scanned roots were subsequently placed in paper bags and oven-dried. The oven temperature was initially set to 105\u0026deg;C for 30 minutes, then reduced to 65\u0026deg;C until a constant dry weight was achieved and weighted. Specific root length (SRL) was defined as root biomass per unit root length, while root tissue density (RTD) was defined as root biomass per unit root volume. After grinding, we sieved the root samples through a 100 \u0026micro;m-mesh screen and stored them in bags for chemical analysis.\u003c/p\u003e \u003cp\u003eRoot carbon content (RC) and root nitrogen content (RN) were measured using an elemental analyzer (EURO EA, Euro Vector, Italy). The root phosphorus content (TP) was quantified using a vanadate-molybdate yellow colorimetric assay after wet digestion with a concentrated H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e-H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e mixture \u003csup\u003e\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e\u003c/sup\u003e. The ratio of root carbon content to root nitrogen content (RCN), the ratio of root carbon content to root phosphorus content (RCP) and the ratio of root nitrogen content to root phosphorus content ratio (RNP) were then calculated.\u003c/p\u003e \u003cp\u003eTen root tips per species were randomly selected from FAA-fixed samples. The tips were dehydrated through an alcohol series and embedded in paraffin. Cross-sections (8 \u0026micro;m thick) were cut at the maturation zone using a microtome \u003csup\u003e\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e\u003c/sup\u003e, stained with safranine-fast green, and imaged under a compound microscope (Axio Lab, A1 Zeiss). The diameter of first-order roots (FD), epidermal thickness (ET), cortical thickness (CT), and vascular bundle diameter (VBD) were measured using ImageJ software (National Institutes of Health, Bethesda, Maryland, USA).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSoil properties analysis\u003c/h2\u003e \u003cp\u003eTotal carbon (TC), nitrogen (TN) and phosphorus (TP) concentrations in the soil were measured in the same way as roots. Carbon content to nitrogen ratio (SCN), carbon content to phosphorus ratio (SCP), and nitrogen content to phosphorus ratio (SNP) were then calculated. Inorganic nitrogen (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{NO}}_{\\text{3}}^{\\text{-}}\\text{-N}\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{NH}}_{\\text{4}}^{+}\\text{-N}\\)\u003c/span\u003e\u003c/span\u003e) was extracted with potassium chloride and analyzed using a continuous flow analyzer (Bran and Luebbe, Norderstedt, Germany). Available phosphorus (AP) was determined via dualacid extraction (hydrochloric acid and concentrated sulfuric acid), followed by the molybdenum\u0026ndash;antimony colorimetric method \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e3\u003c/sup\u003e. Soil pH was measured with a calibrated pH meter (Precision and Scientific Corp, Shanghai, China) in deionized water at a 1:2.5 (w/v) soiltowater ratio. Soil water content was calculated as the mass loss percentage after oven-drying fresh soil at 105\u0026deg;C to constant mass, expressed relative to dry soil mass. Hyphal density (HD, m g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in the soil was determined using the modified grid intersect method \u003csup\u003e74\u003c/sup\u003e with a stereo microscope (Leica EZ4W, Leica Microsystems, Germany).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eA two-way ANOVA was conducted using the \u0026ldquo;car\u0026rdquo; package to evaluate the effects of microplastic addition, mycorrhizal types and their interactions on soil properties and root traits. The effects of microplastic addition and mycorrhizal types on soil properties and root traits were analyzed using paired sample \u003cem\u003et\u003c/em\u003e-tests in R version 4.1.2 \u003csup\u003e75\u003c/sup\u003e. Mantel test analysis was used to explore the relationships between soil properties and root traits for ECM and AM tree species with the \u0026ldquo;vegan\u0026rdquo; package. Redundancy analysis (RDA) was used to identify the primary soil factors driving root trait variations for different mycorrhizal types following microplastic addition. Data were standardized prior to analysis using the \u0026ldquo;vegan\u0026rdquo; package in R. Principal component analysis (PCA) was performed using R packages \u0026ldquo;ggplot2\u0026rdquo; and \u0026ldquo;vegan\u0026rdquo; to explore root trait differences in AM and ECM tree species under microplastic addition.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":" \u003ch2\u003eDeclaration of interests\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\u003ch2\u003eAuthor contributions\u003c/h2\u003e \u003cp\u003eYingtong Zhou: Data curation, Writing-Original draft preparation. Ivano Brunner: Writing- Reviewing and Editing. Ziping Liu: Conceptualization, Visualization. Wei Guo: Software, Validation. Xiaoyue Na: Data curation, Formal analysis. Jiaxin Liu: Investigation, Visualization. Junni Wang: Investigation, Methodology. Cunguo Wang: Funding acquisition, Supervision, Writing- Reviewing and Editing. Mai-He Li: Supervision, Writing- Reviewing and Editing.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThis work was financially supported by the Natural Science Foundation of China (grant number 42171051).\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eThe data in this study will be submitted to the Dryad Digital Repository once the manuscript is accepted.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBergmann, M. \u003cem\u003eet al.\u003c/em\u003e White and wonderful? Microplastics prevail in snow from the Alps to the Arctic. Science Advances 5, doi:doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/sciadv.aax1157\u003c/span\u003e\u003cspan address=\"10.1126/sciadv.aax1157\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRillig, M. C. Microplastic disguising as soil carbon storage. Environ Sci Technol. 52, 6079\u0026ndash;6080, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1021/acs.est.8b02338\u003c/span\u003e\u003cspan address=\"10.1021/acs.est.8b02338\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiese, B. \u003cem\u003eet al.\u003c/em\u003e Uptake of microplastics and impacts on plant traits of savoy cabbage. Ecotoxicol. Environ. Saf. 272, 116086, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ecoenv.2024.116086\u003c/span\u003e\u003cspan address=\"10.1016/j.ecoenv.2024.116086\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMa, R. \u003cem\u003eet al.\u003c/em\u003e Microplastics affect C, N, and P cycling in natural environments: Highlighting the driver of soil hydraulic properties. J. Hazard. Mater. 459, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2023.132326\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2023.132326\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRichard, C. T. \u003cem\u003eet al.\u003c/em\u003e Lost at Sea: Where is all the plastic? Science 304, 838, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/science.1094559\u003c/span\u003e\u003cspan address=\"10.1126/science.1094559\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi, H. \u003cem\u003eet al.\u003c/em\u003e Single and composite damage mechanisms of soil polyethylene/polyvinyl chloride microplastics to the photosynthetic performance of soybean (\u003cem\u003eGlycine max\u003c/em\u003e [L.] merr.). Frontiers in Plant Science 13, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fpls.2022.1100291\u003c/span\u003e\u003cspan address=\"10.3389/fpls.2022.1100291\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi, R. \u003cem\u003eet al.\u003c/em\u003e Visual tracking of label-free microplastics in wheat seedlings and their effects on crop growth and physiology. J. Hazard. Mater. 456, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2023.131675\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2023.131675\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCayuela, C., Levia, D. F., Latron, J. \u0026amp; Llorens, P. Particulate matter fluxes in a mediterranean mountain forest: interspecific differences between throughfall and stemflow in \u003cem\u003eOak\u003c/em\u003e and \u003cem\u003ePine\u003c/em\u003estands. Journal of Geophysical Research: Atmospheres 124, 5106\u0026ndash;5116, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1029/2019jd030276\u003c/span\u003e\u003cspan address=\"10.1029/2019jd030276\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeber, C. J., Rillig, M. C. \u0026amp; Bigalke, M. Mind the gap: forest soils as a hidden hub for global micro- and nanoplastic pollution. Microplastics and Nanoplastics 3, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s43591-023-00067-1\u003c/span\u003e\u003cspan address=\"10.1186/s43591-023-00067-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGreen, J. K. \u0026amp; Keena, T. F. The limits of forest carbon sequestration. Science 376, 692\u0026ndash;693, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/science.abo6547\u003c/span\u003e\u003cspan address=\"10.1126/science.abo6547\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang, W. \u003cem\u003eet al.\u003c/em\u003e Responses of lettuce (\u003cem\u003eLactuca sativa\u003c/em\u003e L.) growth and soil properties to conventional non-biodegradable and new biodegradable microplastics. Environ. Pollut. 341, 122897, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.envpol.2023.122897\u003c/span\u003e\u003cspan address=\"10.1016/j.envpol.2023.122897\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRanauda, M. A. \u003cem\u003eet al.\u003c/em\u003e From the rhizosphere to plant fitness: Implications of microplastics soil pollution. Environ. Exp. Bot. 226, 105874, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.envexpbot.2024.105874\u003c/span\u003e\u003cspan address=\"10.1016/j.envexpbot.2024.105874\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Souza Machado, A. A., Kloas, W., Zarfl, C., Hempel, S. \u0026amp; Rillig, M. C. Microplastics as an emerging threat to terrestrial ecosystems. Glob Chang Biol. 24, 1405\u0026ndash;1416, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/gcb.14020\u003c/span\u003e\u003cspan address=\"10.1111/gcb.14020\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuerrero-Ram\u0026iacute;rez, N. \u003cem\u003eet al.\u003c/em\u003e Global root traits (GRooT) database. Glob Ecol Biogeogr. 30, 25\u0026ndash;37, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/geb.13179\u003c/span\u003e\u003cspan address=\"10.1111/geb.13179\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo, W. \u003cem\u003eet al.\u003c/em\u003e Linking fine-root diameter across root orders with climatic, biological and edaphic factors in the Northern Hemisphere. \u003cem\u003eOikos\u003c/em\u003e 2024, doi\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e:/10.1111/oik.10763\u003c/span\u003e\u003cspan address=\":/10.1111/oik.10763\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu, H. \u003cem\u003eet al.\u003c/em\u003e Effects of microplastics concentration on plant root traits and biomass: Experiment and meta-analysis. Ecotoxicol. Environ. Saf. 285, 117038, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ecoenv.2024.117038\u003c/span\u003e\u003cspan address=\"10.1016/j.ecoenv.2024.117038\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun, H., Lei, C., Xu, J. \u0026amp; Li, R. Foliar uptake and leaf-to-root translocation of nanoplastics with different coating charge in maize plants. J. Hazard. Mater. 416, 125854, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2021.125854\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2021.125854\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRozman, U. \u003cem\u003eet al.\u003c/em\u003e An extensive characterization of various environmentally relevant microplastics \u0026ndash; Material properties, leaching and ecotoxicity testing. Sci. Total Environ. 773, 145576, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scitotenv.2021.145576\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2021.145576\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLehmann, A. \u003cem\u003eet al.\u003c/em\u003e Microplastic fiber and drought effects on plants and soil are only slightly modified by arbuscular mycorrhizal fungi. Soil Ecology Letters 4, 32\u0026ndash;44, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s42832-020-0060-4\u003c/span\u003e\u003cspan address=\"10.1007/s42832-020-0060-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen, H. \u003cem\u003eet al.\u003c/em\u003e Arbuscular mycorrhizal fungi can inhibit the allocation of microplastics from crop roots to aboveground edible parts. Journal of Agricultural and Food Chemistry 71, 18323\u0026ndash;18332, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1021/acs.jafc.3c05570\u003c/span\u003e\u003cspan address=\"10.1021/acs.jafc.3c05570\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUrbina, M. A., Correa, F., Aburto, F. \u0026amp; Ferrio, J. P. Adsorption of polyethylene microbeads and physiological effects on hydroponic maize. Sci. Total Environ. 741, 140216, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scitotenv.2020.140216\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2020.140216\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpan\u0026ograve;, C. \u003cem\u003eet al.\u003c/em\u003e Polystyrene nanoplastics affect seed germination, cell biology and physiology of rice seedlings in-short term treatments: Evidence of their internalization and translocation. Plant Physiol. Biochem. 172, 158\u0026ndash;166, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.plaphy.2022.01.012\u003c/span\u003e\u003cspan address=\"10.1016/j.plaphy.2022.01.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen, W. \u003cem\u003eet al.\u003c/em\u003e Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees. \u003cem\u003eProc. Natl. Acad. Sci.\u003c/em\u003e 113, 8741\u0026ndash;8746, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1073/pnas.1601006113\u003c/span\u003e\u003cspan address=\"10.1073/pnas.1601006113\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKanold, E. P. Microplastic pollution in soil environments: consequences for arbuscular mycorrhizal fungi and plant root traits. University of Guelph (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeifheit, E. F., Lehmann, A. \u0026amp; Rillig, M. C. Potential effects of microplastic on arbuscular mycorrhizal fungi. Front Plant Sci 12, 626709, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fpls.2021.626709\u003c/span\u003e\u003cspan address=\"10.3389/fpls.2021.626709\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Souza Machado, A. A. \u003cem\u003eet al.\u003c/em\u003e Microplastics can change soil properties and affect plant performance. Environmental Science \u0026amp; Technology 53, 6044\u0026ndash;6052, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1021/acs.est.9b01339\u003c/span\u003e\u003cspan address=\"10.1021/acs.est.9b01339\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRead, D. J. Myeorrhizas in ecosystems. Experientia 47, 376\u0026ndash;391, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/BF01972080\u003c/span\u003e\u003cspan address=\"10.1007/BF01972080\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (1991).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChari, N. R., Muratore, T. J. \u0026amp; Taylor, B. N. Long-term soil warming drives different belowground responses in arbuscular mycorrhizal and ectomycorrhizal trees. Global Change Biol. 30, 1\u0026ndash;11, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/gcb.17550\u003c/span\u003e\u003cspan address=\"10.1111/gcb.17550\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePregitzer, K. S. \u003cem\u003eet al.\u003c/em\u003e Fine root architecture of nine north American trees. Ecological monographs 72, 293\u0026ndash;309 (2002).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTerrer, C., Vicca, S., Hungate, B. A., Phillips, R. P. \u0026amp; Prentice, I. C. Mycorrhizal association as a primary control of the CO\u003csub\u003e2\u003c/sub\u003e fertilization effect. Science 353, 72\u0026ndash;74, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/science.aaf4610\u003c/span\u003e\u003cspan address=\"10.1126/science.aaf4610\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAusten, K., MacLean, J., Balanzategui, D. \u0026amp; H\u0026ouml;lker, F. Microplastic inclusion in birch tree roots. Sci. Total Environ. 808, 152085, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scitotenv.2021.152085\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2021.152085\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMidgley, M. G. \u0026amp; Phillips, R. P. Mycorrhizal associations of dominant trees influence nitrate leaching responses to N deposition. Biogeochemistry 117, 241\u0026ndash;253, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10533-013-9931-4\u003c/span\u003e\u003cspan address=\"10.1007/s10533-013-9931-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuyper, T. W. \u0026amp; Jansa, J. Arbuscular mycorrhiza: advances and retreats in our understanding of the ecological functioning of the mother of all root symbioses. Plant and Soil 489, 41\u0026ndash;88, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11104-023-06045-z\u003c/span\u003e\u003cspan address=\"10.1007/s11104-023-06045-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWen, H. \u003cem\u003eet al.\u003c/em\u003e Diverse and high pollution of microplastics in seasonal snow across Northeastern China. Sci. Total Environ. 907, 167923, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scitotenv.2023.167923\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2023.167923\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeber, C., Rillig, M. \u0026amp; Bigalke, M. Mind the gap: forest soils as a hidden hub for global micro- and nanoplastic pollution. Microplast. Nanoplast. 3, 19, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s43591-023-00067-1\u003c/span\u003e\u003cspan address=\"10.1186/s43591-023-00067-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang, Q. \u003cem\u003eet al.\u003c/em\u003e Effects of microplastics and carbon nanotubes on soil geochemical properties and bacterial communities. J. Hazard. Mater. 433, 128826, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2022.128826\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2022.128826\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRead, D. J. Mycorrhizas in ecosystems. Experientia 47, 376\u0026ndash;391, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/BF01972080\u003c/span\u003e\u003cspan address=\"10.1007/BF01972080\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (1991).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChari, N. R. \u003cem\u003eet al.\u003c/em\u003e Long-term soil warming drives different belowground responses in arbuscular mycorrhizal and ectomycorrhizal trees. Global Change Biol. 30, e17550, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/gcb.17550\u003c/span\u003e\u003cspan address=\"10.1111/gcb.17550\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDijkstra, F. A., Carrillo, Y., Pendall, E. \u0026amp; Morgan, J. A. Rhizosphere priming: a nutrient perspective. Frontiers in Microbiology 4, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fmicb.2013.00216\u003c/span\u003e\u003cspan address=\"10.3389/fmicb.2013.00216\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhillips, R. P. \u0026amp; Fahey, T. J. The Influence of Soil Fertility on Rhizosphere Effects in Northern Hardwood Forest Soils. Soil Science Society of America Journal 72, 453\u0026ndash;461, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2136/sssaj2006.0389\u003c/span\u003e\u003cspan address=\"10.2136/sssaj2006.0389\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou, J., Xu, H., Xiang, Y. \u0026amp; Wu, J. Effects of microplastics pollution on plant and soil phosphorus: a meta-analysis. J. Hazard. Mater. 461, 132705, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2023.132705\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2023.132705\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRillig, M. C., Lehmann, A., de Souza Machado, A. A. \u0026amp; Yang, G. Microplastic effects on plants. New Phytol. 223, 1066\u0026ndash;1070, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/nph.15794\u003c/span\u003e\u003cspan address=\"10.1111/nph.15794\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGao, B., Yao, H., Li, Y. \u0026amp; Zhu, Y. Microplastic Addition Alters the Microbial Community Structure and Stimulates Soil Carbon Dioxide Emissions in Vegetable-Growing Soil. Environmental Toxicology and Chemistry 40, 352\u0026ndash;365, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/etc.4916\u003c/span\u003e\u003cspan address=\"10.1002/etc.4916\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQin, W., Hu, C. \u0026amp; Oenema, O. Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat: a meta-analysis. Sci. Rep. 5, 16210, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/srep16210\u003c/span\u003e\u003cspan address=\"10.1038/srep16210\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSajjad, M. \u003cem\u003eet al.\u003c/em\u003e Microplastics in the soil environment: A critical review. Environ. Technol. Innovation 27, 102408, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.eti.2022.102408\u003c/span\u003e\u003cspan address=\"10.1016/j.eti.2022.102408\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang, J. \u003cem\u003eet al.\u003c/em\u003e Effects of plastic residues and microplastics on soil ecosystems: A global meta-analysis. J. Hazard. Mater. 435, 129065, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2022.129065\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2022.129065\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang, F., Wang, Q., Adams, C. A., Sun, Y. \u0026amp; Zhang, S. Effects of microplastics on soil properties: Current knowledge and future perspectives. J. Hazard. Mater. 424, 127531, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2021.127531\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2021.127531\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTong, Y. \u003cem\u003eet al.\u003c/em\u003e Microplastics affect activity and spatial distribution of C, N, and P hydrolases in rice rhizosphere. Soil Ecology Letters 5, 220138, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s42832-022-0138-2\u003c/span\u003e\u003cspan address=\"10.1007/s42832-022-0138-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYan, Y. \u003cem\u003eet al.\u003c/em\u003e Effect of polyvinyl chloride microplastics on bacterial community and nutrient status in two agricultural soils. Bull. Environ. Contam. Toxicol. 107, 602\u0026ndash;609, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00128-020-02900-2\u003c/span\u003e\u003cspan address=\"10.1007/s00128-020-02900-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFei, Y. \u003cem\u003eet al.\u003c/em\u003e Response of soil enzyme activities and bacterial communities to the accumulation of microplastics in an acid cropped soil. Sci. Total Environ. 707, 135634, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scitotenv.2019.135634\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2019.135634\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBosker, T., Bouwman, L. J., Brun, N. R., Behrens, P. \u0026amp; Vijver, M. G. Microplastics accumulate on pores in seed capsule and delay germination and root growth of the terrestrial vascular plant \u003cem\u003eLepidium sativum\u003c/em\u003e. Chemosphere 226, 774\u0026ndash;781, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.chemosphere.2019.03.163\u003c/span\u003e\u003cspan address=\"10.1016/j.chemosphere.2019.03.163\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCeccanti, C. \u003cem\u003eet al.\u003c/em\u003e Polyethylene microplastics alter root functionality and affect strawberry plant physiology and fruit quality traits. J. Hazard. Mater. 470, 134164, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2024.134164\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2024.134164\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, Y. \u003cem\u003eet al.\u003c/em\u003e Microplastics reduce nitrogen uptake in peanut plants by damaging root cells and impairing soil nitrogen cycling. J. Hazard. Mater. 443, 130384, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhazmat.2022.130384\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2022.130384\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeifheit, E. F., Lehmann, A. \u0026amp; Rillig, M. C. Potential effects of microplastic on arbuscular mycorrhizal fungi. Front. Plant Sci. 12, 626709, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fpls.2021.626709\u003c/span\u003e\u003cspan address=\"10.3389/fpls.2021.626709\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLian, P., Xu, L., Yang, L., Yue, K. \u0026amp; Pe\u0026ntilde;uelas, J. Divergent soil P accrual in ectomycorrhizal and arbuscular mycorrhizal trees: insights from a common garden experiment in subtropical China. Front. Plant Sci. 15, 1333505, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fpls.2024.1333505\u003c/span\u003e\u003cspan address=\"10.3389/fpls.2024.1333505\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhillips, R. P., Brzostek, E. \u0026amp; Midgley, M. G. The mycorrhizal-associated nutrient economy: a new framework for predicting carbon\u0026ndash;nutrient couplings in temperate forests. New Phytol. 199, 41\u0026ndash;51, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/nph.12221\u003c/span\u003e\u003cspan address=\"10.1111/nph.12221\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu, X. \u003cem\u003eet al.\u003c/em\u003e Extraradical hyphae exhibit more plastic nutrient-acquisition strategies than roots under nitrogen enrichment in ectomycorrhiza-dominated forests. Global Change Biol. 29, 4605\u0026ndash;4619, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/gcb.16768\u003c/span\u003e\u003cspan address=\"10.1111/gcb.16768\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFinzi, A. \u003cem\u003eet al.\u003c/em\u003e Rhizosphere processes are quantitatively important components of terrestrial carbon and nutrient cycles. Global Change Biol. 21, 2082\u0026ndash;2094, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/gcb.12816\u003c/span\u003e\u003cspan address=\"10.1111/gcb.12816\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFort, F. \u003cem\u003eet al.\u003c/em\u003e Root traits are related to plant water-use among rangeland Mediterranean species. Functional Ecology 31, 1700\u0026ndash;1709, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/1365-2435.12888\u003c/span\u003e\u003cspan address=\"10.1111/1365-2435.12888\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBergmann, J. \u003cem\u003eet al.\u003c/em\u003e The fungal collaboration gradient dominates the root economics space in plants. Science Advances 6, eaba3756, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/sciadv.aba3756\u003c/span\u003e\u003cspan address=\"10.1126/sciadv.aba3756\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeng, P. \u0026amp; Jin, G. Fine root morphology and chemical responses to N addition depend on root function and soil depth in a Korean pine plantation in Northeast China. Forest Ecology and Management 520, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.foreco.2022.120407\u003c/span\u003e\u003cspan address=\"10.1016/j.foreco.2022.120407\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJonathan, A. B. \u003cem\u003eet al.\u003c/em\u003e Plant-soil feedbacks and mycorrhizal type influence temperate forest population dynamics. Science 355, 181\u0026ndash;184, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1126/science.aai8212\u003c/span\u003e\u003cspan address=\"10.1126/science.aai8212\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFahey, C., Bell, F. W. \u0026amp; Antunes, P. M. Effects of dual mycorrhizal inoculation on Pinus strobus seedlings are influenced by soil resource availability. Plant and Soil 479, 607\u0026ndash;620, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11104-022-05546-7\u003c/span\u003e\u003cspan address=\"10.1007/s11104-022-05546-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTisserant, E. \u003cem\u003eet al.\u003c/em\u003e Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis. \u003cem\u003eProceedings of the National Academy of Sciences\u003c/em\u003e 110, 20117\u0026ndash;20122, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1073/pnas.1313452110\u003c/span\u003e\u003cspan address=\"10.1073/pnas.1313452110\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMathur, S., Tomar, R. S. \u0026amp; Jajoo, A. Arbuscular mycorrhizal fungi (AMF) protects photosynthetic apparatus of wheat under drought stress. Photosynth Res 139, 227\u0026ndash;238, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11120-018-0538-4\u003c/span\u003e\u003cspan address=\"10.1007/s11120-018-0538-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXie, K. \u003cem\u003eet al.\u003c/em\u003e Plant nitrogen nutrition: The roles of arbuscular mycorrhizal fungi. J. Plant Physiol. 269, 153591, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jplph.2021.153591\u003c/span\u003e\u003cspan address=\"10.1016/j.jplph.2021.153591\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSmith, S. E., Smith, F. A. \u0026amp; Jakobsen, I. Functional diversity in arbuscular mycorrhizal (AM) symbioses: the contribution of the mycorrhizal P uptake pathway is not correlated with mycorrhizal responses in growth or total P uptake. New Phytol. 162, 511\u0026ndash;524, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1469-8137.2004.01039.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1469-8137.2004.01039.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJing, M., Shi, Z., Zhang, M., Zhang, M. \u0026amp; Wang, X. Nitrogen and Phosphorus of Plants Associated with Arbuscular and Ectomycorrhizas Are Differentially Influenced by Drought. \u003cem\u003ePlants\u003c/em\u003e 11, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/plants11182429\u003c/span\u003e\u003cspan address=\"10.3390/plants11182429\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFu, W. \u003cem\u003eet al.\u003c/em\u003e Community response of arbuscular mycorrhizal fungi to extreme drought in a cold-temperate grassland. New Phytol 234, 2003\u0026ndash;2017, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/nph.17692\u003c/span\u003e\u003cspan address=\"10.1111/nph.17692\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eComas, L. H. \u0026amp; Eissenstat, D. M. Linking fine root traits to maximum potential growth rate among 11 mature temperate tree species. Functional Ecology 18, 388\u0026ndash;397, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.0269-8463.2004.00835.x\u003c/span\u003e\u003cspan address=\"10.1111/j.0269-8463.2004.00835.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLu Ru, k. \u003cem\u003eAnalytical methods for soil and agriculture chemitry.\u003c/em\u003e, Vol. 4 312\u0026ndash;314 (China Agricultural Science and Technology Press, 2000).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGu, J., Xu, Y., Dong, X., Wang, H. \u0026amp; Wang, Z. Root diameter variations explained by anatomy and phylogeny of 50 tropical and temperate tree species. Tree Physiol 34, 415\u0026ndash;425, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/treephys/tpu019\u003c/span\u003e\u003cspan address=\"10.1093/treephys/tpu019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMehlich, A. Mehlich 3 soil test extractant: A modification of Mehlich 2 extractant. Communications in Soil Science and Plant Analysis 15, 1409\u0026ndash;1416, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1080/00103628409367568\u003c/span\u003e\u003cspan address=\"10.1080/00103628409367568\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrundrett, M. Practical methods in mycorrhiza research: based on a workshop organized in conjunction with the ninth North American Conference on mycorrhizae, University of Guelph, Guelph, Ontario, Canada., (1994).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eR: A language and environment for statistical computing (R Foundation for Statistical Computing, 2021).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"arbuscular mycorrhizal, ectomycorrhizal, nitrogen, nutrient acquisition strategy, phosphorus","lastPublishedDoi":"10.21203/rs.3.rs-6627952/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6627952/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWhile the impacts of microplastics on aquatic and agricultural ecosystems are well studied, the impacts on forest ecosystems involving soil and trees are scarcely investigated. Here, we assessed the impacts of microplastic addition on rhizosphere soil properties, and chemical, morphological and anatomical traits of fine roots for ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) tree species in a mixed temperate forest. We found that the concentration of available nitrogen in the soil rhizosphere increased, while the concentration of available phosphorus decreased in the ECM tree species after the addition of microplastics. The opposite pattern was true for AM tree species. Fine roots of ECM tree species exhibited shorter root length, smaller root diameter, lower root tissue density, lower branching ratio, lower branching intensity, and lower phosphorus concentration, but higher hyphal density, higher root carbon/nitrogen, and higher root carbon/phosphorus ratios with the addition of microplastics mediated by total phosphorus in the soil. Fine roots of AM tree species exhibited higher specific root length, tip density, epidermal thickness, vascular bundle diameter and root carbon/nitrogen ratio, but lower root diameter, branching intensity, cortical thickness, root tissue density and root phosphorus concentration after microplastic addition, which was mediated by soil water content, nitrate nitrogen and available phosphorus. These findings on mycorrhizal-specific responses to microplastic addition will deepen our understanding of carbon and nutrient cycling and species composition dynamics with increasing microplastic pollution in temperate mixed forest ecosystems.\u003c/p\u003e","manuscriptTitle":"Mycorrhizal-specific responses of rhizosphere soil properties and fine-root traits to polystyrene microplastic addition in a temperate mixed forest","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-23 14:12:55","doi":"10.21203/rs.3.rs-6627952/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"communications-earth-and-environment","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"commsenv","sideBox":"Learn more about [Communications Earth and Environment](https://www.nature.com/commsenv/)","snPcode":"","submissionUrl":"","title":"Communications Earth \u0026 Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Communications Series","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bb0e1d24-041b-47d2-bc4c-32aaca788135","owner":[],"postedDate":"May 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":48704184,"name":"Earth and environmental sciences/Biogeochemistry/Element cycles"},{"id":48704185,"name":"Earth and environmental sciences/Ecology/Forest ecology"}],"tags":[],"updatedAt":"2026-02-28T08:13:37+00:00","versionOfRecord":{"articleIdentity":"rs-6627952","link":"https://doi.org/10.1038/s43247-026-03237-0","journal":{"identity":"communications-earth-and-environment","isVorOnly":false,"title":"Communications Earth \u0026 Environment"},"publishedOn":"2026-01-27 05:00:00","publishedOnDateReadable":"January 27th, 2026"},"versionCreatedAt":"2025-05-23 14:12:55","video":"","vorDoi":"10.1038/s43247-026-03237-0","vorDoiUrl":"https://doi.org/10.1038/s43247-026-03237-0","workflowStages":[]},"version":"v1","identity":"rs-6627952","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6627952","identity":"rs-6627952","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}