Drought represents a paramount abiotic stressor constraining global agroforestry productivity. Plants have evolved multifaceted adaptive strategies involving active modulation of symbiotic microbial communities to mitigate drought stress. These plant-associated microbes enhance plant drought adaptation via five principal mechanisms: (i) extracellular polymeric substance-mediated biofilm formation on plant surface enhances hydroregulation and edaphic structural stability; (ii) osmoprotectant biosynthesis (e.g., proline) maintains cellular osmotic equilibrium; (iii) synthesizing antioxidants to reduce damage from reactive oxygen species and oxidative stress; (iv) regulating plant phytohormone metabolism by secreting hormones (e.g. indole-3-acetic acid) and 1-aminocyclopropane-1-carboxylic deaminase; (v) emitting signaling molecules (e.g. volatile organic compounds, hormones and enzymes) to activate plant drought adaptation. Future researches should focus on the development of host-specific drought-adaptive microbial consortia while elucidating phyllosphere–rhizosphere microbiome crosstalk, ultimately harnessing translational microbiome engineering to evaluate their efficacy in multi-environment agricultural systems.

We screened 161 eligible papers of experimental data across the Tibetan plateau for Meta-analysis, in order to systematically assess and validate potential application of plant resource allocation strategies, such as the optimal allocation hypothesis, the isometric allocation hypothesis, and the allometric allocation hypothesis under environmental changes, and to explore the effects of environmental factors (temperature change, grazing intensity) on plant resource allocation strategies in alpine grassland ecosystems on the Tibetan Plateau. Overall, we found that the aboveground and belowground growth relationship in alpine grasslands follows the allometric growth hypothesis, which was unaffected by warming, grazing and their interactions. In addition, the biomass transferred between aboveground and belowground, the former was decreased, while the later was increased under warming condition in alpine steppe implies that the resource allocation strategy in alpine steppe grassland may potentially follow the optimal allocation hypothesis. We further found that the effect of soil properties on biomass, not the biomass allocation, was different under warming and grazing condition in alpine grasslands, which further conforms the above conclusion. In addition, warming helped to mitigate the negative effects of grazing, which indicated that the interaction between warming and grazing is important in alpine grassland ecosystems. Overall, results of this study are of theoretical significance for understanding how moderate grazing affects the growth of plants in alpine grasslands under changing climate.

The mechanisms of plant adaptation to environmental gradients have been the focus of ecological research, with environmental stresses driving coordinated or differentiated regulation of plant functional traits. Plant resource acquisition involves root trait plasticity and mycorrhizal symbiosis. However, root trait plasticity along precipitation gradients and root-mycorrhizal trade-offs remain unclear. We conducted community surveys along a west-east precipitation gradient in four natural grassland communities (alpine desert steppe, alpine steppe, alpine meadow steppe and alpine meadow) on the plateau in northern Xizang Plateau. Six key root traits (root diameter, RD; root dry matter content, RDMC; root tissue density, RTD; specific root length, SRL; root branching intensity, RBI; and root length colonization percentage, RLC) were measured in 18 alpine plant species to investigate the coordination and trade-offs between root traits and mycorrhizal fungi along the precipitation gradient. Our results showed community-level declines in RDMC, RD, RTD and RLC with increasing precipitation, contrasting with elevated RBI and SRL. Functional groups exhibited distinct patterns: grasses and legumes demonstrated root-mycorrhizal trade-offs, sedges displayed synergy and forbs showed inconsistent responses. Divergent trends in plant root traits and mycorrhizal fungi were observed at the species level. Alpine plants in humid eastern meadows favored root elongation, while those in arid western desert steppe relied on radial growth and mycorrhizal fungal cooperation for resource acquisition. These findings highlight varied root absorption strategies among alpine plants along environmental gradients, supporting the importance of ecological niche diversification in maintaining alpine ecosystem diversity and stability.

Terrestrial plants are colonized by various microorganisms in the rhizosphere, phyllosphere and endosphere. Variations of microorganisms between these niches could affect plant performance. While studies have indicated that microorganisms associated with invasive plants may facilitate their invasion success, niche effects on the composition, function and co-occurrence network of invasive plant microbiomes remain poorly understood. In this study, we investigated the bacterial and fungal communities in the rhizosphere soil, root and leaf endospheres of two invasive plants, Flaveria bidentis and Eclipta prostrata. Flaveria bidentis is a recently introduced species (introduced in 2001), whereas E. prostrata has been invaded in China for over 1000 years. We found that microbial community of F. bidentis and E. prostrata harbored more specialists, fewer unique amplicon sequence variants (ASVs), and lower diversity and network complexity in the leaf endosphere than that in the rhizosphere soil. Moreover, the bacterial and fungal communities in the rhizosphere soil, root and leaf endospheres of F. bidentis were more diverse, included more unique ASVs, and had a higher network complexity than those of E. prostrata. Predicted functional profiles revealed that there were more beneficial bacteria and fewer pathogenic fungi associated with F. bidentis than those with E. prostrata. These results demonstrate that there is a significant niche differentiation in the two invasive plant microbiotas, and this work may also indicate potential impact of residence time of invasive plants on plant-microbe interactions.

A widely accepted perspective posits that an extension of the growing season enhances plant growth by increasing the duration of favorable environmental conditions under warming, which is described as an ecological effect. However, changes in growing season length can also influence plant functional traits and physiological processes, as suggested by the "leaf economics spectrum" theory, a physiological aspect frequently overlooked. Disentangling the ecological and physiological effects of growing season length on plant growth remains challenging due to their co-variation with climate factors. Here we explored the physiological effect through common garden experiments on the Qinghai−Tibetan Plateau. Our findings revealed a trade-off between growing season length and plant growth under controlled climatic conditions, a pattern further corroborated by satellite-based observations across most regions of the plateau. This trade-off was driven by a negative correlation between growing season length and photosynthetic efficiency, suggesting that an extended growing season does not necessarily translate into enhanced carbon assimilation. However, state-of-the-art dynamic global vegetation models failed to adequately capture this trade-off, underscoring the need to integrate the physiological effects of growing season length into these model frameworks for improved predictions of plant growth under climate change.

Seedling adaptation to precipitation change is of great significance in the development and succession of tropical forests under global climate changes. Here, we conducted a field-based experiment to assess the performance of different functional seedlings (Cassia siamea, nitrogen (N)-fixing, and Syzygium hancei, non-N-fixing species) to altered precipitation patterns (control; wetter wet season, WW; delayed wet season, DW) in a secondary tropical forest of southern China. The results showed that WW and DW treatments significantly increased the leaf mass per area of S. hancei; however, precipitation treatment significantly decreased the leaf chlorophyll (chl) a content in C. siamea but significantly increased the leaf chl b and total chl contents in S. hancei. WW treatment significantly increased the relative growth rate of height and total biomass of S. hancei. Additionally, WW and DW treatments significantly increased the leaf soluble sugar contents of both species. DW treatment significantly increased the starch content of the leaves and coarse roots of S. hancei and significantly enhanced the leaf non-structural carbohydrate (NSC) contents of both species. WW treatment upregulated the allocation of soluble sugar, starch, and NSC in the leaves and fine roots in C. siamea. Thus, variations in NSC storage and allocation among organs in two species may directly reflect the different adaptation mechanisms to altered precipitation. Our results indicate that S. hancei adjusts the NSC contents, while C. siamea shifts the NSC allocation among different organs to adapt to the altered precipitation in tropical forests.

Invasions by non-native plant species are thought to be facilitated by factors like escape from specialized natural enemies and increased resource availability. However, the success of invasive plants also depends on interactions with native plants and soil organisms, including nematodes. Plants can experience both beneficial and harmful interactions with nematodes. Yet, research on how nematodes and nutrient levels interact to affect competition between invasive and native plants is lacking. We conducted a multi-species greenhouse experiment involving 10 invasive species and 20 native species to test the separate and combined effects of nutrient levels and nematodes on performance of individual invasive plant species, as well as their competition with native plant communities. High-nutrient conditions significantly enhanced the aboveground biomass (+119.4%), height (+26.9%), reproduction (+21.0%) and proportional aboveground biomass (+21.2%) of invasive plant species. Conversely, competition from native plant communities significantly reduced the mean aboveground biomass, height, and reproduction of the invasive species by 55.3%, 20.3% and 13.5%, respectively. For invasive plants grown without competition, the high-nutrient treatment significantly enhanced total biomass and root diameter, although it decreased the root mass fraction, independent of nematode presence. In addition, in the absence of competition, nematodes increased the specific root length of invasive plants by 3.6% under low-nutrient conditions but reduced it by 10.1% under high-nutrient conditions. These results indicate that nutrient enrichment, competition and biotic interactions with nematodes can all play critical roles in shaping the growth and adaptive strategies of invasive plant species.

Green stem photosynthesis is well known, but the effect of stem photosynthesis on plant growth and development remains uncertain. In this study, green stems of semiannual Rosa chinensis were subjected to a shading treatment to explore the effect of stem photosynthesis on the growth and biomass accumulation. The results showed that (1) Stem photosynthesis affected biomass accumulation and allocation in R. chinensis. The stem shading treatment decreased the biomass of R. chinensis by approximately 18.7%. The proportion of biomass allocated to the stems increased while the proportion of biomass allocated to the leaves and roots decreased. (2) Stem photosynthesis facilitates an increase in nonstructural carbohydrate concentration, chlorophyll a concentration and chlorophyll a/b of R. chinensis. (3) The net photosynthesis in the stems of R. chinensis was negative, and biomass accumulation was significantly positively correlated with the dark respiration rate in stems, indicating that stem photosynthesis fixed CO₂ released internally by respiration. This study reveals that stem photosynthesis in R. chinensis enhances biomass accumulation by promoting chlorophyll fluorescence and dark respiration rates in the stems. Furthermore, stem photosynthesis contributes to the balanced allocation of biomass by enhancing the proportional distribution of biomass to leaves and roots.

Microplastics in terrestrial ecosystems are relatively understudied compared to microplastics in well-studied marine and freshwater ecosystems. It is well-documented that soil microplastics can profoundly influence agricultural plant species; while terrestrial wild plants are primary producers and at the bottom of food chains, remarkably little is known about how microplastic abundances affect their growth and the related mechanisms. We selected 18 wild plant species, exposed them to an environmentally realistic microplastic gradient (ranging from 0 to 8000 items kg^–1 soil) for one growing season, and measured soil pH, nutrients and microbes, leaf fluorescence, and plant biomass. We also used structural equation modeling to link the associations between variables. 11% of the 18 wild plant species were inhibited by polypropylene (PP) microplastics, 39% were facilitated, and 50% were unaffected. Across all the 18 species, PP microplastics had no negative impacts on their whole-plant growth, as measured by the standardized effect size; microplastic abundance impacts on whole-plant growth exhibited hump-shaped reaction norms, and the abundance thresholds for positive impacts approximately ranged from 2000 to 6000 items kg^–1 soil. Soil pH played a key role in mediating microplastic impacts directly and indirectly by altering leaf chlorophyll and root nutrient uptake. These findings suggest that microplastic abundance thresholds could shape the whole-plant growth of terrestrial wild plants and microplastic abundance impacts might not rise consistently. Additionally, threshold effects highlight the importance of the full gamut of microplastic abundance gradients and provide insights into ecosystem management strategies.

Invasive plants may exhibit priority effects and begin growth before native plants. Priority effects may be an important way that invasive species outcompete native plants. We tested priority effects on the invasive grass Smooth Brome Bromus inermis (cool season C₃), the cosmopolitan and invasive Bermuda grass Cynodon dactylon (warm season C₄) and a native grass species, Red Fescue Festuca rubra (cool season C₃), in the greenhouse. We grew each species alone, with a conspecific neighbor (intraspecific competition), concurrently with one of the two other heterospecifics (interspecific competition), and with a priority effect of one species being present 21 days before the heterospecific neighbor (priority effects). We recorded relative growth rates (RGR), as well as above- and belowground dry biomass. We also used a relative interaction index (RII) to determine the competitive abilities of each of these species. Smooth Brome was significantly heavier than Bermuda and Red Fescue, although Bermuda grass had the highest RGR of the three species. All three species showed stronger effects of intraspecific competition than interspecific competition. Most of the effects were competitive relative to plants grown alone. However, none of these three species exhibited priority effects, unlike a previous study. We conclude that increased competitive ability, particularly of Smooth Brome, may be sufficient to exclude native grasses.

Biochar is a highly effective soil amendment that has been widely used for ecological remediation and has shown great potential in promoting plant nutrient acquisition and growth. However, it remains unclear whether biochar addition influences competition between invasive and native plants and thus is suitable for restoration of communities invaded by exotic plants. We conducted a field experiment and a ¹⁵N labelling test to investigate the impact of biochar addition on N uptake of invasive Spartina alterniflora and native Phragmites australis under both intra- and interspecific competition. Biochar addition significantly promoted the NO₃⁻-N uptake rate of both P. australis and S. alterniflora under interspecific competition, and promoted the NH₄⁺-N uptake rate of both P. australis and S. alterniflora under both intra- and interspecific competition. However, biochar addition did not influence the competitive balance between S. alterniflora and P. australis. We conclude that biochar addition can enhance N uptake of both native and invasive plants, but cannot alter their competitive superiority in N acquisition or shift their N form preferences. The findings suggest that biochar application will not be useful if we target at restoring wetlands due to exotic plant invasions, as it cannot enhance the competitive advantages of natives over invasives. However, biochar may be applied if we target at restoring degraded wetlands caused by other disturbances such as such as salinization and nutrient impoverishment, as it will not enhance the competitive advantage of invasives over natives.

While the alerting effects of microbe-induced plant volatiles (MIPVs) to biotic stressors have been extensively studied, the ecological functions of MIPVs responding to abiotic stressors have received less attention. Using an interplant communication assay setup, we employed Phytolacca americana as a study species to investigate whether heavy metal-induced MIPVs released by the emitter plants contribute to metal tolerance in neighboring receiver plants. We found that high levels of manganese (Mn) stress increased the total MIPV emissions of plants cultivated in non-sterilized soil, in contrast to VOCs emitted by plants in sterilized soil. MIPVs produced by the Mn-stressed plants notably altered the hormonal profiles of the receiver plants, leading to increased similarity in soil microbial assembles and modification of CSR strategies. Consequently, the receiver plants exhibited enhanced tolerance to subsequent Mn stress, as evidenced by improved growth performance, increased antioxidant enzyme activities, and reduced membrane damage. By unraveling the mechanism underlying MIPV-mediated tolerance priming for neighboring plants, we reveal a key signal role of soil microorganisms involved in plant-plant communication. This study represents one of the initial efforts to elucidate the alerting effects of MIPVs induced by heavy metal stress on neighboring plants and its ecological consequences.

Microclimate can profoundly impact carbon (C) cycling in terrestrial ecosystems. However, due to the complex thermal conduction among air, water, and sediment, the responses of wetland microclimate to the driving forces of global change remain largely unexplored. Here, based on a two-year (2022-2023) field manipulative experiment in a freshwater wetland in the North China Plain, this study aimed to investigate the effects of simulated climate warming and atmospheric nitrogen (N) deposition on the temperatures of shallow-water, deep-water, and sediment. The nighttime warming effect increased the daily mean temperatures of the shallow-water, deep-water, and sediment layers by 0.71°C, 0.73°C, and 0.64°C, respectively. In addition, the diurnal temperature range of the deep-water layer was reduced by 0.17°C. In contrast, N addition did not affect the above parameters of shallow-water, deep-water, or sediment. The impact of N addition showed seasonal fluctuations. Warming-induced temperature increase was influenced mainly by solar radiation and water turbidity. Changes in submerged plant cover had a cooling effect at various vertical levels. In addition, increased wetland temperature may affect the rate of microbial metabolism to significantly increase the rate of carbon emissions. The present study offers empirical evidence concerning temperature changes at varying vertical levels within freshwater wetlands in the context of climate warming. Our findings emphasize the necessity of integrating data on shallow-water, deep-water, and sediment temperatures into the forecasting of wetland carbon cycling responses to global change.

Urbanization-induced warming advanced the timing of spring budburst, impacting on urban ecosystems. However, how urban artificial light affects the spring budburst and its spatial variation within species distribution are less studied, especially lacking experimental evidences. Here, we conducted a climate-controlled experiment using twigs collected from artificial light (AL) and no-artificial light (NoAL) conditions at three latitudinal gradients (L_high, L_middle and L_low) in China. We found that the temperature responsiveness of spring budburst (T_res, defined as the number of days to budburst after the twigs are placed into the chambers, with a smaller value indicating stronger responsiveness) was significantly stronger for NoAL individuals (54.3 days) than AL individuals (60.7 days). Additionally, AL twigs exhibited a greater photoperiod limitation (12.7 days vs. 7.6 days) and a higher heat requirement (732.15 K vs. 679.15 K) than NoAL twigs, suggesting that individuals exposed to artificial light may have adapted to longer photoperiod and increased the heat requirement for budburst. More importantly, T_res difference between AL and NoAL individuals was more pronounced in northern sites (5.8 days at L_high, 12.2 days at L_middle) than in southern sites (0.7 days at L_low), possibly due to higher inter-annual temperature variability at higher latitudes. Our findings provide experimental evidence of the effect of artificial light on tree budburst and highlight the need to consider the adaptability of urban trees when studying phenological responses to climate change in urban environments.

Biodiversity underpins critical ecological processes, yet its relationship with phosphorus (P) remains poorly understood globally. In particular, it is essential to explore how plant diversity and soil microbial diversity respond distinctly to changes in P availability on a global scale. This study combines meta-analysis and natural gradient analysis to assess the responses of plant and soil microbial diversity to altered P supply at a global scale. Specifically, we conducted a meta-analysis using 393 observations from 128 field P addition experiments, complemented by a natural gradient analysis of forest tree diversity and vascular plant diversity. Our results showed that P additions reduced plant richness by 8.5% and the Shannon index by 1.3% in global grasslands, while exerting minimal effects on soil bacterial and fungal diversity across major terrestrial ecosystems worldwide. Natural gradient analysis showed that both forest tree richness and vascular plant richness were significantly related to soil total P concentration, either positively or negatively, depend on the environmental variables controlled for partial correlation analyses. These findings collectively suggest that plant diversity exhibits greater sensitivity to altered soil P availability than soil microbial diversity. Therefore, improved understanding of the distinct responses of above- and below-ground biodiversity to altered nutrient supply provides a scientific foundation for implementing sound management practices of terrestrial functions and processes.

The Yangtze River Basin (YZRB) and Yellow River Basin (YRB) are the largest river basins in China, representing typical regions in southern and northern China. Understanding the impacts of climate and phenology on net primary productivity (NPP) is essential for regional ecological protection, management and carbon neutrality. Based on remote sensing and climate data, this study quantified the temporal trends and spatial variations in vegetation phenology and NPP. Pearson correlation and structural equation modeling were employed to examine the mechanisms through which climate and phenology influence NPP. The results reveal distinct NPP accumulation mechanisms in the YZRB and YRB. In the YZRB, the growing season significantly lengthened (0.60 days yr^-1, P < 0.05), resulting in an annual NPP increase of 3.19 gC m^-2 yr^-1, primarily driven by spring NPP (52% contribution), with direct effects of temperature (β = 0.71, P < 0.001) and radiation (β = 0.63, P < 0.001) on NPP. In contrast, the YRB exhibited balanced seasonal NPP growth (3.54 gC m^-2 yr^-1 for annual NPP), with precipitation regulating NPP through both direct and phenology-mediated indirect pathways (indirect β = 0.27, P < 0.05). These findings emphasize the complexity of the effects of climate and phenology on NPP, underscoring the necessity for region-specific management strategies to optimize productivity under climate change.

Cactaceae is an important plant family in the semi-arid ecosystems of the Americas. However, few studies have analyzed their responses after wildfires. In this study, we assessed the survival rate and resprouting capacity of cacti from different growth forms one year after a wildfire in the Córdoba Mountains, central Argentina. Eight species are present in the study area, which were classified into four growth forms; then we established 158 plots and recorded the status (dead or alive) of each cactus, and size-related variables. We also documented microenvironmental characteristics (percentage cover of grasses, forbs, shrubs, rock and bare ground) and topographic information (slope and slope orientation) for each plot, estimating the resprouting capacity of each growth form. Survival rates and resprouting capacity varied among growth forms. The survival rate for arborescent growth form was 25%, while for globose, opuntioid and short columnar forms were 84%, 69% and 55%, respectively. Microenvironmental and topographic factors influenced resprouting capacity, though effects varied among growth forms. Globose growth form showed the highest recovery capacity after the wildfire, contrasting with arborescent growth form, of which only 2% of the individuals resprouted, predominantly on south- and north-facing slopes. In contrast, short columnar and opuntioid growth forms showed no significant relationship between survival or resprouting capacity, and the measured variables. These findings provide key insights into the role of fire in shaping cacti populations and highlight the need to consider species-specific and environmental interactions in conservation and management strategies for the Chaco forest.

Co-existing forest tree species associated with ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi may have different nitrogen (N) acquisition strategies for various soil nitrogen (N) forms which can be difficult to determine under field conditions. Paired (ammonium/nitrate) ¹⁵N labeling to soils demonstrated that common conifers in Northeast China associated with ECM fungi took up more nitrate than ammonium. The N uptake strategy of co-existing broadleaved species, associated with either AM fungi or ECM fungi, remains to be determined. We conducted paired ¹⁵N labeling on seedlings of six common broadleaved species and four conifer species to reveal more nitrate uptake than ammonium by all ten species. Nitrate uptake contributed 49~83% (average 69%) to N uptake by these species, ranking in the order of AM broadleaved species (average 79%), ECM broadleaved species (average 70%) and ECM conifer species (average 60%). Random forest analysis suggested plant functional groups, mycorrhizal types and fine root to shoot ratios as important factors supporting the higher nitrate uptake by these species. Our results provided convincing evidence of substantial nitrate assimilation to different extents by common conifer and broadleaved tree species in Northeast China.

Arbuscular mycorrhizal fungi (AMF) and Bacillus play a crucial role in promoting the growth and defense of exotic plants, and their interaction may further enhance plant invasions. Soil nitrogen level is an important factor that affects the interaction. However, the effect of the interaction on the growth and defensive ability of exotic plants under different nitrogen levels remains unclear. In this study, a pot experiment was conducted using Rhizoglomus intraradices (RI) and Bacillus megaterium (BM), one of the dominant AMF and Bacillus in the rhizosphere of Flaveria bidentis, with three soil nitrogen levels (0, 3.75 and 7.5 g m⁻²) and four inoculation treatments (uninoculated, inoculation with RI, inoculation with BM and co-inoculated with RI and BM). Significant correlations were observed between microbial inoculations and indicators of plant growth and defense across varying soil nitrogen levels. Co-inoculation notably enhanced both plant growth and defense compared to single inoculations, especially under the nitrogen concentration of 3.75 g m⁻². Specifically, compared to single inoculation, co-inoculation increased the biomass of F. bidentis by 8.27% and 16.4%, as well as the flavonoids concentration by 21.89%–30.95% and phenolic acids concentration by 54.22%–60.93%, respectively. These enhancements in growth and defensive compound production likely promote the competitive ability of F. bidentis and its resistance to biotic and abiotic stresses, thereby contributing to its successful invasion.

Trait-based functional diversity (FD) is an important predictor of tree species ecological multifunctionality (TS-EMF), but its relationship may be mediated by environmental factors. Currently, the study of threshold-dependent relationship between FD and TS-EMF along urban and suburban gradients and their environmental regulatory mechanisms is still quite limited. In this study, 12 typical tree species from urban and suburban forests in Shenyang were used to calculate TS-EMF by combining the multithreshold and averaging method, and to assess community FD, aiming to reveal the role of FD on TS-EMF and how environmental factors regulate TS-EMF through FD and community-weighted mean (CWM) traits. The results showed that urban TS-EMF was generally higher than suburban (P < 0.05). There were differences in the driving mechanisms of TS-EMF at different threshold levels, with air humidity (total effect: 0.435) and CWM P_n (net photosynthetic rate, relative importance: 24.42%) being the key drivers at high threshold levels. At low threshold levels, functional evenness (FEve) played a dominant role, but the extent to which influenced TS-EMF depended on the type and number of tree species within the TS-EMF threshold range. Notably, the effects of CWM P_n and FEve on TS-EMF showed threshold dependence, with thresholds of 61.18% and 64.47%, respectively. Additionally, the urban–suburban gradient could significantly influence the driving mechanism: the direct effect of environmental factors and CWM traits prevailed in urban forests, while suburban forests showed a multifactorial cascade effect. The study showed that the formation of TS-EMF in urban forests is the result of multifactorial coupling of traits, FD and environmental factors, and this finding provides a new theoretical perspective for understanding the ecosystem service drivers of urban forests.

Increasing nitrogen (N) deposition exacerbates phosphorus (P) limitations in subtropical Chinese fir plantations, yet clonal mechanisms mediating root adaptation to heterogeneous P environments remain unclear. This study investigates the growth and metabolic responses of three clones (Y061/Y020: P-efficient; Y2C: P-sensitive) under N deposition and contrasting P distributions. Elevated N deposition enhanced aboveground and belowground biomass under heterogeneous P conditions, particularly enhancing Y061’s root length and surface area. Elevated N deposition significantly increased APase activity while decreasing organic acid secretion, particularly under homogeneous P-deficient conditions. Heterogeneous P supply amplified clonal divergence: P-efficient clones exhibited higher phosphorus absorption efficiency (PAE) than Y2C through root morphological plasticity, while N deposition upregulated APase activity but reduced total organic acids secretion. Metabolomic revealed N-driven shifts in exudate profiles, with lactic, malonic, succinic, and oxalic acid increasing while shikimic, quinic and malic acids decreased. Notably, nitrogen absorption efficiency (NAE) synergistically enhanced PAE under high N conditions. Clones Y061 and Y020 demonstrated superior N and P absorption capabilities, while clone Y2C prioritized enzymatic P mobilization in homogeneous deficiency but showed compromised growth. We demonstrate that N deposition restructures root foraging strategies along a “morphological-enzymatic” axis, where P-efficient clones exploit spatial nutrient heterogeneity through root proliferation rather than organic acid investment. These findings provide actionable solutions: (1) Deploying Y061 and Y020 clones in high-N regions improves productivity; (2) Mixed plantations mimicking heterogeneous P distribution enhance nutrient resilience. Our findings contribute to a deeper understanding of nutrient dynamics and providing targeted strategies for sustainable forestry in acidified subtropical soils.

Spring frost involves low temperatures in spring. Research shows cold snaps can alter herbaceous plants' biomass allocation, impacting grassland ecosystems. However, the exact effects of frost timing and severity remain unclear. This study simulated spring frost based on characteristics of spring frost on the northern slope of the Tianshan Mountains to examine how alfalfa (Medicago sativa) and ryegrass (Lolium spp.) adjust biomass allocation under varying frost intensities and timings, including interspecific differences in these responses. The findings revealed that (1) compared to the control group (which did not undergo low-temperature treatment), alfalfa was more sensitive to high-intensity spring frost, exhibiting a significant decrease of 13.6% in the root weight ratio and increases of 8.65% and 4.96% in the stem and leaf weight ratios, respectively. In contrast, ryegrass displayed an inverse trend, although the changes were not significant. (2) Early stage spring frost (immediately after thinning) significantly affected alfalfa biomass allocation, leading to an 11.28% decrease in the root weight ratio, whereas it also significant increases of 3.78% the stem weight ratio by 7.51% and leaf weight ratio. In contrast, late stage spring frost (applied on the 17rd day after thinning) had a relatively greater effect on ryegrass, with the root weight ratio increasing by 4.13% and the stem weight ratio decreasing by 4.18%. These findings reveal plants' distinct adaptations to cryogenic stresses, improving our understanding of herbaceous growth responses to extreme weather in arid zones and offering data to support grassland ecosystem services in Xinjiang.

Traditional studies of plant elemental composition have mainly focused on the concentrations of C, N and P and stoichiometric ratios among different plant species. Little attention was paid to the intraspecific variation of the elementome and the underlying mechanisms including phenotypic plasticity and adaptive evolution. We conducted salinity manipulation experiments in two common gardens with two lineages of a widespread grass (Phragmites australis), measuring ten element concentrations of the leaves and roots. The genetic distances and epigenetic distances were calculated from SSR and MS-AFLP markers, respectively. In a principal component analysis, the root elemental contents contributed to the first two principal components (PC1 and PC2), and the leaf elemental contents contributed to PC3 and PC4. The PC1 was affected by salinity, while the PC2 was affected by salinity, climate and their interaction. The PC3 was affected by salinity, while the PC4 was affected by lineage. Mantel tests showed a significant correlation between epigenetic and environmental distances as well as between epigenetic and genetic distances. The contribution of genetics to epigenetic variation was larger than the environment. Genetic and epigenetic variation was associated with different PCs. The elementome is decoupled between leaf and root, and the root elementome had a larger variability. The leaf epigenetic variation depends on the genetic variation, and is also induced by the external environmental changes. Intraspecific elementome variation reflects environment more than genetic and epigenetic variation. These insights shed light on the underlying ecological mechanisms that drive the intraspecific variation of the elementome.