全球变化环境驱动因子(气候变暖、降水格局、氮沉降加剧等)对植物养分吸收利用策略的影响：科学问题、研究方案与生态学意义

… nutrient uptake responds to global change. In this review various components of global change, … and their effects on kinetics of root nutrient uptake are examined. The response of root …

… plant responses to global change plays in changing and/or buffering the availability and stoichiometry of nutrients … The capacity to invest to increase nutrient uptake is also limited in arid …

… that nutrient limitation may have on plant biomass. Here we review plant nutrient acquisition strategies … and real-world elevated CO 2 . Many of the strategies that are key to alleviating …

Warming-induced desiccation of the fertile topsoil layer could lead to decreased nutrient diffusion, mobility, mineralization and uptake by roots. Increased vertical decoupling between nutrients in topsoil and water availability in subsoil/bedrock layers under warming could thereby reduce cumulative nutrient uptake over the growing season. We used a Mediterranean semiarid shrubland as model system to assess the impacts of warming-induced topsoil desiccation on plant water and nutrient use patterns. A 6-year manipulative field experiment examined the effects of warming (2.5 ºC), rainfall reduction (30%) and their combination on soil resource utilization by Helianthemum squamatum shrubs. A drier fertile topsoil ("growth pool") under warming led to greater proportional utilization of water from deeper, wetter, but less fertile subsoil/bedrock layers ("maintenance pool") by plants. This was linked to decreased cumulative nutrient uptake, increased non-stomatal (nutritional) limitation of photosynthesis and reduced water use efficiency, aboveground biomass growth and drought survival. Whereas a shift to greater utilization of water stored in deep subsoil/bedrock may buffer the negative impact of warming-induced topsoil desiccation on transpiration, this plastic response cannot compensate for the associated reduction in cumulative nutrient uptake and carbon assimilation, which may compromise the capacity of plants to adjust to a warmer and drier climate.

… in just one parameter, eg, root-to-shoot ratio, can elucidate the mechanism and/or the extent of the effects of global change on plant nutrient uptake, much the same way that we do not …

… nutrient supply as limiting root function. The theory predicts no change in root:shoot allocation where water uptake is the limiting root function, but substantial shifts where nutrient uptake …

Producing enough food to meet the needs of an increasing global population is one of the greatest challenges we currently face. The issue of food security is further complicated by impacts of elevated CO2 and climate change. In this viewpoint article, we begin to explore the impacts of elevated CO2 on two specific aspects of plant nutrition and resource allocation that have traditionally been considered separately. First, we focus on arbuscular mycorrhizas, which play a major role in plant nutrient acquisition. We then turn our attention to the allocation of resources (specifically N and C) in planta, with an emphasis on the secondary metabolites involved in plant defence against herbivores. In doing so, we seek to encourage a more integrated approach to investigation of all aspects of plant responses to eCO2.

Predicting the effects of multiple global change stressors on microbial communities remains a challenge because of the complex interactions among those factors. Here, we explore the combined effects of major global change stressors on nutrient acquisition traits in marine phytoplankton. Nutrient limitation constrains phytoplankton production in large parts of the present-day oceans, and is expected to increase owing to climate change, potentially favouring small phytoplankton that are better adapted to oligotrophic conditions. However, other stressors, such as elevated pCO2, rising temperatures and higher light levels, may reduce general metabolic and photosynthetic costs, allowing the reallocation of energy to the acquisition of increasingly limiting nutrients. We propose that this energy reallocation in response to major global change stressors may be more effective in large-celled phytoplankton species and, thus, could indirectly benefit large-more than small-celled phytoplankton, offsetting, at least partially, competitive disadvantages of large cells in a future ocean. Thus, considering the size-dependent responses to multiple stressors may provide a more nuanced understanding of how different microbial groups would fare in the future climate and what effects that would have on ecosystem functioning. This article is part of the theme issue ‘Conceptual challenges in microbial community ecology’.

… on plant nutrient uptake … climate change might affect root growth, root N and P uptake rate per unit biomass and mycorrhizal colonization, after 5 years exposure to experimental warming…

… plant phenology by global climate change may alter the ability of plants to acquire soil resources (water and nutrients… also strongly affects the acquisition of nutrients acquired in bulk flow…

… limited nutrient for plant growth, and global climate changes … of plant P acquisition strategies to climate changes and … acquisition mechanism of plants and their response to global …

… treatment effect on plant nutrient uptake, we … climate change and predict its consequences on the different compartments involved in nutrient dynamics (ie nutrient input to soil and plant …

… of plant growth, plant nutrient acquisition, and soil nutrient loss to the amount and pattern of water supply. We predicted that the effect of AM on plant … increase plant N and P uptake more …

… enrichment and warming was in a similar trend to that with warming alone. Our findings suggest that nutrient uptake and utilization by rice are more impacted by warming compared with …

… Foliar [N] and N : P increased, and δ 15 N and [P] decreased in the two forests close to … N deposition in the region is 15 N-depleted, these data suggest that the increased foliar [N] and N …

Abstract. The role of plants in sequestering carbon is a critical component in mitigating climate change. A key aspect of this role involves plant nitrogen (N) uptake (Nup) and N use efficiency (NUE), as these factors directly influence the capacity of plants to store carbon. However, the additive contribution of N deposition, soil factors (biotic and abiotic), and climate to the plant N cycle remains inadequately understood, introducing significant uncertainties into climate change projections. Here, we used ground-based observations across 159 field experiments (including above and belowground information) to calculate Nup and NUE and identify their main drivers in natural ecosystems. We found that global plant Nup is primarily driven by N deposition, mean temperature, and precipitation, with Nup increasing in warmer and wetter areas. In contrast, NUE is driven by soil biotic and abiotic factors. Specifically, NUE decreased with the intensity of colonization by arbuscular mycorrhizal fungi and increased with soil pH and soil microbial stocks. Nup and NUE presented opposite latitudinal distributions, with Nup higher on tropical latitudes and NUE higher towards the poles. Total soil N stocks were not found to be a driver of Nup or NUE. We also compared our results with TRENDY models and found that models may overestimate Nup by ∼ 100 Tg N yr−1 in the tropics and triple the standard deviation at boreal latitudes. Our findings emphasize the effect of N deposition and soil microbes that, in addition to climate and soil pH, are crucial for accurately predicting ecosystems' capacity to sequester carbon and mitigate climate change at a global scale.

… shifts in the C/N/P stoichiometry of A. … N deposition gradient result in altered nutrient use efficiency during photosynthesis. The leaf traits, nutrient status, and physiological performance of …

… Nitrogen (N) deposition in forests shifts the nutrient balance of entire ecosystems, promoting … of 14 years of N deposition (10 g N m −2 y −1 ) in multiple forms on nutrient stoichiometry in …

… -unit N deposition (referred to as ecosystem N use efficiency, ENUE, … fertilizer uses and changing climate and land use, in this study, we intend to examine how increasing N deposition …

Human activities have more than doubled reactive nitrogen (N) deposited in ecosystems, perturbing the N cycle and considerably impacting plant, animal, and microbial communities. However, biotic responses to N deposition can vary widely depending on factors including local climate and soils, limiting our ability to predict ecosystem responses. Here, we synthesize reported impacts of elevated N on grasslands and draw upon evidence from the globally distributed Nutrient Network experiment (NutNet) to provide insight into causes of variation and their relative importance across scales. This synthesis highlights that climate and elevated N frequently interact, modifying biotic responses to N. It also demonstrates the importance of edaphic context and widespread interactions with other limiting nutrients in controlling biotic responses to N deposition.

… and reduce nutrient and water availability and uptake, leading to low … , N 2 fixation by legumes, use of heavy levels of organic and inorganic N fertilizers, and atmospheric deposition of N …

… N deposition, and nutrient status in the Pearl River Delta of Southern China were collected to determine tree ring δ 13 C and δ 15 N … 2 ], climate, and N deposition were related to the long…

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.

… our two indices of plasticity (proportion of plant roots placed in nutrient enriched patches and the range in N uptake rates measured) in either pulsed or stable nutrient treatments. …

To overcome soil nutrient limitation, many plants have developed complex nutrient acquisition strategies including altering root morphology, root hair formation or colonization by arbuscular mycorrhizal fungi (AMF). The interactions of these strategies and their plasticity are, however, affected by soil nutrient status throughout plant growth. Such plasticity is decisive for plant phosphorus (P) acquisition in P‐limited soils. We investigated the P acquisition strategies and their plasticity of two maize genotypes characterized by the presence or absence of root hairs. We hypothesized that in the absence of root hairs plant growth is facilitated by traits with complementary functions, e.g., by higher root mycorrhizal colonization. This dependence on complementary traits will decrease in P fertilized soils. At early growth stages, root hairs are of little benefit for nutrient uptake. Regardless of the presence or absence of root hairs, plants produced average root biomass of 0.14 g per plant and exhibited 23% root mycorrhizal colonization. At later growth stages of maize, contrasting mechanisms with functional complementarity explained similar plant biomass production under P limitation: the presence of root hairs versus higher root mycorrhizal colonization (67%) favored by increased fine root diameter in absence of root hairs. P fertilization decreased the dependence of plant on specific root traits for nutrient acquisition. Through root trait plasticity, plants can minimize trade‐offs for developing and maintaining functional traits, while increasing the benefit in terms of nutrient acquisition and plant growth. The present study highlights the plasticity of functional root traits for efficient nutrient acquisition strategies in agricultural systems with low nutrient availability. (Less)

Root plasticity, a trait that can respond to selective pressure, may help plants forage for nutrients in heterogeneous soils. Agricultural breeding programs have artificially selected for increased yield under comparatively homogeneous soil conditions, potentially decreasing the capacity for plasticity in crop plants like barley (Hordeum vulgare). However, the effects of domestication on the evolution of root plasticity are essentially unknown. Using a split container approach, we examined the differences in root plasticity among three domestication levels of barley germplasm (wild, landrace, and cultivar) grown under different concentrations and distribution patterns of soil nutrients. Domestication level, nutrient concentration, and nutrient distribution interactively affected average root diameter; differential root allocation (within‐plant plasticity) was greatest in wild barley (Hordeum spontaneum), especially under low nutrient levels. Correlations of within‐plant root plasticity and plant size were most pronounced in modern cultivars under low‐nutrient conditions. Barley plants invested more resources to root systems when grown in low‐nutrient soils and allocated more roots to higher‐nutrient locations. Root plasticity in barley is scale dependent and varies with domestication level. Although wild barley harbors a greater capacity for within‐plant root plasticity than domesticated barley, cultivars exhibited the greatest capacity to translate within‐plant plasticity into increased plant size.

Global change drivers create new environmental scenarios and selective pressures, affecting plant species in various interacting ways. Plants respond with changes in phenology, physiology, and reproduction, with consequences for biotic interactions and community composition. We review information on phenotypic plasticity, a primary means by which plants cope with global change scenarios, recommending promising approaches for investigating the evolution of plasticity and describing constraints to its evolution. We discuss the important but largely ignored role of phenotypic plasticity in range shifts and review the extensive literature on invasive species as models of evolutionary change in novel environments. Plasticity can play a role both in the short‐term response of plant populations to global change as well as in their long‐term fate through the maintenance of genetic variation. In new environmental conditions, plasticity of certain functional traits may be beneficial (i.e., the plastic response is accompanied by a fitness advantage) and thus selected for. Plasticity can also be relevant in the establishment and persistence of plants in novel environments that are crucial for populations at the colonizing edge in range shifts induced by climate change. Experimental studies show taxonomically widespread plastic responses to global change drivers in many functional traits, though there is a lack of empirical support for many theoretical models on the evolution of phenotypic plasticity. Future studies should assess the adaptive value and evolutionary potential of plasticity under complex, realistic global change scenarios. Promising tools include resurrection protocols and artificial selection experiments.

Optimal plant development requires root uptake of 14 essential mineral elements from the soil. Since the bioavailability of these nutrients underlies large variation in space and time, plants must dynamically adjust their root system architecture to optimize nutrient access and acquisition. The information on external nutrient availability and whole-plant demand is translated into cellular signals that often involve phytohormones as intermediates to trigger a systemic or locally restricted developmental response. Timing and extent of such local root responses depend on the overall nutritional status of the plant that is transmitted from shoots to roots in the form of phytohormones or other systemic long-distance signals. The integration of these systemic and local signals then determines cell division or elongation rates in primary and lateral roots, the initiation, emergence or elongation of lateral roots as well as the formation of root hairs. Here, we review the cascades of nutrient-related sensing and signaling events that involve hormones and highlight nutrient-hormone relations that coordinate root developmental plasticity in plants.

… indirect effects on soil P availability, global warming threatens phytodiversity via enhanced P availability. The effects of global warming on soil nutrients might lead to better conditions for …

Aims Drought stress is one of the most limiting factors for agriculture and ecosystem productivity. Climate change exacerbates this threat by inducing increasingly intense and frequent drought events. Root plasticity during both drought and post-drought recovery is regarded as fundamental to understanding plant climate resilience and maximizing production. We mapped the different research areas and trends that focus on the role of roots in plant response to drought and rewatering and asked if important topics were overlooked. Methods We performed a comprehensive bibliometric analysis based on journal articles indexed in the Web of Science platform from 1900-2022. We evaluated a) research areas and temporal evolution of keyword frequencies, b) temporal evolution and scientific mapping of the outputs over time, c) trends in the research topics analysis, d) marked journals and citation analysis, and e) competitive countries and dominant institutions to understand the temporal trends of root plasticity during both drought and recovery in the past 120 years. Results Plant physiological factors, especially in the aboveground part (such as “photosynthesis”, “gas-exchange”, “abscisic-acid”) in model plants Arabidopsis, crops such as wheat and maize, and trees were found to be the most popular study areas; they were also combined with other abiotic factors such as salinity, nitrogen, and climate change, while dynamic root growth and root system architecture responses received less attention. Co-occurrence network analysis showed that three clusters were classified for the keywords including 1) photosynthesis response; 2) physiological traits tolerance (e.g. abscisic acid); 3) root hydraulic transport. Thematically, themes evolved from classical agricultural and ecological research via molecular physiology to root plasticity during drought and recovery. The most productive (number of publications) and cited countries and institutions were situated on drylands in the USA, China, and Australia. In the past decades, scientists approached the topic mostly from a soil-plant hydraulic perspective and strongly focused on aboveground physiological regulation, whereas the actual belowground processes seemed to have been the elephant in the room. There is a strong need for better investigation into root and rhizosphere traits during drought and recovery using novel root phenotyping methods and mathematical modeling.

Abstract Abiotic stresses increasingly threaten existing ecological and agricultural systems across the globe. Plant roots perceive these stresses in the soil and adapt their architecture accordingly. This review provides insights into recent discoveries showing the importance of root system architecture (RSA) and plasticity for the survival and development of plants under heat, cold, drought, salt, and flooding stress. In addition, we review the molecular regulation and hormonal pathways involved in controlling RSA plasticity, main root growth, branching and lateral root growth, root hair development, and formation of adventitious roots. Several stresses affect root anatomy by causing aerenchyma formation, lignin and suberin deposition, and Casparian strip modulation. Roots can also actively grow toward favorable soil conditions and avoid environments detrimental to their development. Recent advances in understanding the cellular mechanisms behind these different root tropisms are discussed. Understanding root plasticity will be instrumental for the development of crops that are resilient in the face of abiotic stress.

Climate change is threatening crop productivity worldwide and new solutions to adapt crops to these environmental changes are urgently needed. Elevated temperatures driven by climate change affect developmental and physiological plant processes that, ultimately, impact on crop yield and quality. Plant roots are responsible for water and nutrients uptake, but changes in soil temperatures alters this process limiting crop growth. With the predicted variable climatic forecast, the development of an efficient root system better adapted to changing soil and environmental conditions is crucial for enhancing crop productivity. Root traits associated with improved adaptation to rising temperatures are increasingly being analyzed to obtain more suitable crop varieties. In this review, we will summarize the current knowledge about the effect of increasing temperatures on root growth and their impact on crop yield. First, we will describe the main alterations in root architecture that different crops undergo in response to warmer soils. Then, we will outline the main coordinated physiological and metabolic changes taking place in roots and aerial parts that modulate the global response of the plant to increased temperatures. We will discuss on some of the main regulatory mechanisms controlling root adaptation to warmer soils, including the activation of heat and oxidative pathways to prevent damage of root cells and disruption of root growth; the interplay between hormonal regulatory pathways and the global changes on gene expression and protein homeostasis. We will also consider that in the field, increasing temperatures are usually associated with other abiotic and biotic stresses such as drought, salinity, nutrient deficiencies, and pathogen infections. We will present recent advances on how the root system is able to integrate and respond to complex and different stimuli in order to adapt to an increasingly changing environment. Finally, we will discuss the new prospects and challenges in this field as well as the more promising pathways for future research.

… context of rapid climate change, phenotypic plasticity can be … underlying phenotypic plasticity, as relevant to climate change. We … of plasticity in key traits in response to climate change …

Aim: Leaf nutrient resorption is a key nutrient conservation trait, which also influences nutrient cycling rates and pools. Most global biogeochemical models assume that resorption is non‐varying at a temporal scale. However, this trait can differ substantially within populations among years. We assessed the commonality of attaining proficient resorption, the factors associated with proficient resorption, as well as the variability of this trait and the factors controlling trait variability. Location: Global. Time period: 1965–2009. Major taxa studied: Plants. Methods: We compiled multi‐year nutrient resorption data from the literature, representing 50 studies, 94 unique study locations, and 141 species from 53 families and 29 orders. We used multiple linear regression to relate resorption data, as well as the variability in this trait, expressed as the coefficient of variation, to environmental factors. Results: Resource availability was a key driver of resorption, with nutrient‐poor soils associated with more complete resorption and lower resorption plasticity. Nitrogen and phosphorus resorption differentially responded to some drivers, such as leaf habit, soil order and mycorrhizal status. Main conclusions: Overall, environmental and biological factors representing a strong selective force for nutrient conservation, such as nutrient‐poor soil orders, semi‐arid soil moisture regimes, or lack of plant mutualists, were associated with complete resorption, whereas incomplete resorption was associated with weak selective forces, such as nutrient‐rich soil orders, or factors impeding this physiological process (e.g., drought). Inter‐annual variability in resorption was common, particularly for phosphorus. This plasticity has implications for ecosystem nutrient cycling and plant productivity, and accounting for this plasticity in dynamic models of nutrient cycling will improve predictions of nutrient limitations and productivity under future climate conditions.

Abstract Sustaining grassland production in a changing climate requires an understanding of plant adaptation strategies, including trait plasticity under warmer and drier conditions. However, our knowledge to date disproportionately relies on aboveground responses, despite the importance of belowground traits in maintaining aboveground growth, especially in grazed systems. We subjected a perennial pasture grass, Festuca arundinacea, to year-round warming (+3 °C) and cool-season drought (60% rainfall reduction) in a factorial field experiment to test the hypotheses that: (i) drought and warming increase carbon allocation belowground and shift root traits towards greater resource acquisition and (ii) increased belowground carbon reserves support post-drought aboveground recovery. Drought and warming reduced plant production and biomass allocation belowground. Drought increased specific root length and reduced root diameter in warmed plots but increased root starch concentrations under ambient temperature. Higher diameter and soluble sugar concentrations of roots and starch storage in crowns explained aboveground production under climate extremes. However, the lack of association between post-drought aboveground biomass and belowground carbon and nitrogen reserves contrasted with our predictions. These findings demonstrate that root trait plasticity and belowground carbon reserves play a key role in aboveground production during climate stress, helping predict pasture responses and inform management decisions under future climates.

… with nutrient stress the increased allocation to roots seems … increase in root length than the change in root morphology. … to the environment and the expectation of high plasticity in root …

… Globally, extreme land–water alternation, driven by human activities and climate change, has escalated two dominant stresses, flooding and nutrient loss, during plant production (Boyer …

… climate change models for parts of Europe and eastern North America, will depend on the drought susceptibility of the root … ) and nutrient content for several years without root limitation …

The allocation of biomass reflects a plant’s resource utilization strategy and is significantly influenced by climatic factors. However, it remains unclear how climate factors affect the aboveground and belowground biomass allocation patterns on macro scales. To address this, a study was conducted using aboveground and belowground biomass data for 486 species across 294 sites in China, investigating the effects of climate change on biomass allocation patterns. The results show that the proportion of belowground biomass in the total biomass (BGBP) or root-to-shoot ratio (R/S) in the northwest region of China is significantly higher than that in the southeast region. Significant differences (p < 0.05) were found in BGBP or R/S among different types of plants (trees, shrubs, and herbs plants), with values for herb plants being significantly higher than shrubs and tree species. On macro scales, precipitation and soil nutrient factors (i.e., soil nitrogen and phosphorus content) are positively correlated with BGBP or R/S, while temperature and functional traits are negatively correlated. Climate factors contribute more to driving plant biomass allocation strategies than soil and functional trait factors. Climate factors determine BGBP by changing other functional traits of plants. However, climate factors influence R/S mainly by affecting the availability of soil nutrients. The results quantify the productivity and carbon sequestration capacity of terrestrial ecosystems and provide important theoretical guidance for the management of forests, shrubs, and herbaceous plants.

Elucidating the variation of allocation pattern of ecosystem net primary productivity (NPP) and its underlying mechanisms are critically important for understanding the changes of aboveground and belowground ecosystem functions. Under optimal partitioning theory, plants should allocate more NPP to the organ that acquires the most limiting resource, and this expectation has been widely used to explain and predict NPP allocation under changing precipitation. However, confirmatory evidence for this theory has mostly come from observed spatial variation in the relationship between precipitation and NPP allocation across ecosystems, rather than directly from the influences of changing precipitation on NPP allocation within systems. We performed a six-year five-level precipitation manipulation experiment in a semiarid steppe to test whether changes in NPP allocation can be explained by the optimal partitioning theory, and how water requirement of plant community is maintained if NPP allocation is unaltered. The total 30 precipitation levels (five-level × six-year) were divided into dry, nominal and wet precipitation ranges, relative to historical precipitation variation over the past six decades. We found that NPP in both aboveground (ANPP) and belowground (BNPP) increased nonlinearly as precipitation decreased, while the allocation of NPP to BNPP (fBNPP ) showed a concave quadratic relationship with precipitation. The declined fBNPP as precipitation increased in the dry range supported the optimal partitioning theory. However, in the nominal range, NPP allocation was not influenced by the changed precipitation; instead, BNPP was distributed more in the surface soil horizon (0-10 cm) as precipitation increased, and conversely more in the deeper soil layers (10-30 cm) as precipitation decreased. This response in root foraging appears to be a strategy to satisfy plant water requirements and partially explains the stable NPP allocation patterns. Overall, our results suggest that plants can adjust their vertical BNPP distribution in response to drought stress, and that only under extreme drought does the optimal partitioning theory strictly apply, highlighting the context dependency of the adaption and growth of plants under changing precipitation. This article is protected by copyright. All rights reserved.

Precipitation changes modify C, N, and P cycles, which regulate the functions and structure of terrestrial ecosystems. Although altered precipitation affects above‐ and belowground C:N:P stoichiometry, considerable uncertainties remain regarding plant–microbial nutrient allocation strategies under increased (IPPT) and decreased (DPPT) precipitation. We meta‐analyzed 827 observations from 235 field studies to investigate the effects of IPPT and DPPT on the C:N:P stoichiometry of plants, soils, and microorganisms. DPPT reduced leaf C:N ratio, but increased the leaf and root N:P ratios reflecting stronger decrease of P compared with N mobility in soil under drought. IPPT increased microbial biomass C (+13%), N (+15%), P (26%), and the C:N ratio, whereas DPPT decreased microbial biomass N (−12%) and the N:P ratio. The C:N and N:P ratios of plant leaves were more sensitive to medium DPPT than to IPPT because drought increased plant N content, particularly in humid areas. The responses of plant and soil C:N:P stoichiometry to altered precipitation did not fit the double asymmetry model with a positive asymmetry under IPPT and a negative asymmetry under extreme DPPT. Soil microorganisms were more sensitive to IPPT than to DPPT, but they were more sensitive to extreme DPPT than extreme IPPT, consistent with the double asymmetry model. Soil microorganisms maintained stoichiometric homeostasis, whereas N:P ratios of plants follow that of the soils under altered precipitation. In conclusion, specific N allocation strategies of plants and microbial communities as well as N and P availability in soil critically mediate C:N:P stoichiometry by altered precipitation that need to be considered by prediction of ecosystem functions and C cycling under future climate change scenarios.

Plant nutrient resorption, a process by which plant withdraws nutrients from senescing structures to developing tissues, can significantly affect plant growth, litter decomposition and nutrient cycling. Global change factors, such as nitrogen (N) deposition and altered precipitation, may mediate plant nutrient resorption and allocation. The ongoing global change is accompanied with increased N inputs and drought frequency in many regions. However, the interactive effects of increased N availability and drought on plant nutrient-responses remain largely unclear. In a pot experiment, we examined the impacts of N enrichment and drought on leaf N and phosphorous (P) resorption and root nutrient allocation in four species from the Qinghai-Tibet Plateau, including two graminoid species (Kobresia capillifolia and Elymus nutans) and two forb species (Delphinium kamaonense and Aster diplostephioides). Our results showed divergent resorption patterns within the two functional groups. E. nutans and D. kamaonense showed stronger N resorption than K. capillifolia and A. diplostephioides. N addition did not alter their N resorption efficiencies, but decreased the N resorption proficiencies of the former two species. In contrast, drought did not affect N or P resorption proficiencies, but decreased N resorption efficiency of K. capillifolia. Besides, N addition facilitated P resorption in K. capillifolia and D. kamaonense, and drought did the same in A. diplostephioides, suggesting that P resorption plays an important role in nutrient conservation in these species. Moreover, species with stronger N resorption allocated more biomass C or N to aboveground and enhanced their litter quality under N enrichment, while species with weaker resorption allocated more biomass C and/or N to belowground part under drought. Together, these results show that the responses of nutrient resorption and allocation to N enrichment and drought are highly species-specific. Future studies should take these differential responses into consideration to better predict litter decomposition and ecosystem nutrient cycling.

… Increased precipitation could improve the leaf N and P resorption efficiency to cope with the reproduction allocation, and the root nutrients are more sensitive to increased precipitation. …

In theory, changes in the amount of rainfall can change plant biomass allocation and subsequently influence coupled plant-soil microbial processes. However, testing patterns of combined responses of plants and soils remains a knowledge gap for terrestrial ecosystems. We carried out a comprehensive review of the available literature and conducted a meta-analysis to explore combined plant and soil microbial responses in grasslands exposed to experimental precipitation changes. We measured the effects of experimental precipitation changes on plant biomass, biomass allocation, and soil microbial biomass and tested for trade-offs between plant and soil responses to altered precipitation. We found that aboveground and belowground plant biomass responded asynchronically to precipitation changes, thereby leading to shifts in plant biomass allocation. Belowground plant biomass did not change under precipitation changes, but aboveground plant biomass decreased in precipitation reduction and increased in precipitation addition. There was a trade-off between responses of aboveground plant biomass and belowground plant biomass to precipitation reduction, but correlation wasn't found for precipitation addition. Microbial biomass carbon (C) did not change under the treatments of precipitation reduction. Increased root allocation may buffer drought stress for soil microbes through root exudations and neutralize microbial responses to precipitation reduction. However, precipitation addition increased microbial biomass C, potentially reflecting the removal of water limitation for soil microbial growth. We found that there were positive correlations between responses of aboveground plant biomass and microbial biomass C to precipitation addition, indicating that increased shoot growth probably promoted microbial responses via litter inputs. In sum, our study suggested that aboveground, belowground plant biomass and soil microbial biomass can respond asynchronically to precipitation changes, and emphasizes that testing the plant-soil system as a whole is necessary for forecasting the effects of precipitation changes on grassland systems.

Extreme climate events and nitrogen (N) deposition are increasingly affecting the structure and function of terrestrial ecosystems. However, the response of plant biomass to variations to these global change drivers is still unclear in semi-arid regions, especially in degraded sandy grasslands. In this study, a manipulative field experiment run over two years (from 2017 to 2018) was conducted to examine the effect of rainfall alteration and nitrogen addition on biomass allocation of annuals and perennial plants in Horqin sandy grassland, Northern China. Our experiment simulated extreme rainfall and extreme drought (a 60% reduction or increment in the growing season rainfall with respect to a control background) and N addition (20 g/m2) during the growing seasons. We found that the sufficient rainfall during late July and August compensates for biomass losses caused by insufficient water in May and June. When rainfall distribution is relatively uniform during the growing season, extreme rainfall increased aboveground biomass (AGB) and belowground biomass (BGB) of annuals, while extreme drought reduced AGB and BGB of perennials. Rainfall alteration had no significant impacts on the root-shoot ratio (R/S) of sandy grassland plants, while N addition reduced R/S of grassland species when there was sufficient rainfall in the early growing season. The biomass of annuals was more sensitive to rainfall alteration and nitrogen addition than the biomass of perennials. Our findings emphasize the importance of monthly rainfall distribution patterns during the growing season, which not only directly affect the growth and development of grassland plants, but also affect the nitrogen availability of grassland plants.

… within ecosystems, and by affecting growth of and allocation … changes in nutrient availability with increasing rainfall by measuring available soil concentrations of rock-derived nutrients, …

… At W +50% and W +100% treatments, plants were limited by soil available nutrients. The “… plants can adapt to precipitation change using high variation and optimal biomass allocation…

… of roots to maximize resource acquisition under changes in water availability (Songsri … changes in the timing of precipitation on plant biomass allocation and the vertical root distribution …

Abstract The Tibetan Plateau is considered as one of most sensitive region to global change. Nutrient (N and P) availability is an important limiting ecological factor in cold terrestrial ecosystems such as the alpine belt of the Tibetan Plateau. We focused on Corydallis hendersonii, an endemic alpine species of the Tibetan Plateau. Exploring the N and P below- and above-ground responses of C. hendersonii to climatic factors is crucial for biodiversity conservation of the alpine Tibetan plateau under global change. We used the Outlying Mean Index and regression analyses to assess N and P stoichiometry and biomass responses in leaves and roots of C. hendersonii along climatic gradients. We found that investment and allocation of nutrient and biomass in C. hendersonii were mainly driven by rainfall continentality. In the eastern less-continental wet area of the Tibetan plateau, C. hendersonii had higher biomass in leaf, and lower N and P investment in roots than in the western more continental dry part. Specifically, 300 mm year−1 Mean annual precipitation (MAP) and ca. 80° Rainfall continentality index (GAMS) were threshold values of climate stress inducing strong nutrient limitation for C. hendersonii across the Tibetan Plateau. Our results suggest that rainfall continentality is the primary climatic driver of variation in biomass and nutrients allocation of C. hendersonii on the Tibetan Plateau. Thus, global warming and drying should induce a decrease in total biomass, a reduction in leaf N and P concentrations and an increase in root/shoot ratio in the alpine region of the Tibetan Plateau.

… It is likely that the relatively low plant density and low allocation to roots in our young … ) limited root exploration and access to nutrient patches by plants in the mesocosm periphery (de …

… to soil pH changes in semi-arid grasslands mainly via altering the response of … and precipitation generally allocate more C to belowground than wet grasslands regardless of pH change. …

… precipitation in modulating the nutrient resorption proficiency of plants under potentially increased nutrient … Therefore, global changes in precipitation and N, and corresponding litter …

Precipitation as a key determinant of forest productivity influences forest ecosystems also indirectly through alteration of the nutrient status of the soil, but this interaction is not well understood. Along a steep precipitation gradient, we studied the consequences of reduced precipitation for the soil and biomass nutrient pools and dynamics in 14 mature European beech (Fagus sylvatica L.) forests on Triassic sandstone. We tested the hypotheses that lowered summer precipitation (1) is associated with less acid soils and (2) a reduced accumulation of organic matter on the forest floor, and (3) reduces nutrient supply from the soil and leads to decreasing foliar and root nutrient concentrations. Soil acidity, the amount of forest floor organic matter, and the associated organic matter N and P pools decreased to about a half from wet to dry sites; the C/P and N/P ratios, but not the C/N ratio, of forest floor organic matter were reduced as well. Net N mineralization and P and K pools in the mineral soil did not change with decreasing precipitation. Foliar P and K concentrations (beech sun leaves) increased while N remained constant, resulting in decreasing foliar N/P and N/K ratios. Estimated N resorption efficiency increased toward the dry sites. We conclude that a reduction in summer rainfall significantly reduces the soil C, N and P pools but does not result in decreasing foliar N and P contents in beech. However, the decreasing foliar N/P ratios towards the dry stands indicate that the importance of P limitation for tree growth declines with decreasing precipitation.

… change. To better understand how salt marshes will respond to warming and associated shifts in precipitation, … We exposed two plant communities (one dominated by Spartina patens – …

Temperature and precipitation are expected to increase in the forthcoming decades in the northeastern Qinghai-Tibetan Plateau, with uncertain effects of their interaction on plant and soil carbon:nitrogen:phosphorus (C:N:P) stoichiometry in alpine ecosystems. A two-year field experiment was conducted to examine the effects of warming, precipitation increase, and their interaction on soil and plant C:N:P stoichiometry at functional groups and community level in an alpine meadow. Warming increased aboveground biomass of legumes and N:P ratios of grasses and community, but did not affect soil C:N:P stoichiometry. The piecewise structural equation model (SEM) indicated that the positive effect of warming on community N:P ratio was mainly resulted from its positive influence on the aboveground biomass of functional groups. Precipitation increase reduced C:N ratios of soil, grasses, and community, indicating the alleviation in soil N-limitation and the reduction in N use efficiency of plant. SEM also demonstrated the decisive role of grasses C:N:P stoichiometry on the response of community C:N:P stoichiometry to precipitation increase. The interaction of warming and precipitation increase did not alter plant community and soil, N:P and C:P ratios, which was resulting from their antagonistic effects. The stable soil and plant community C:N:P stoichiometry raised important implications that the effect of warming was offset by precipitation increase. Our study highlights the importance of considering the interaction between warming and precipitation increase when predicting the impacts of climate change on biogeochemical cycles in alpine meadow ecosystems.

… It is our hope that mycorrhizal symbioses can be effectively integrated into global change … Furthermore, for most plant species, mycorrhizas are critical for nutrient uptake. Maximising …

… nutrient uptake of non-mycorrhizal and mycorrhizal plants, the infection level is the only root parameter determined and higher nutrient uptake in mycorrhizal … not taken of nutrient fluxes …

Substantial amounts of nutrients are lost from soils through leaching. These losses can be environmentally damaging, causing groundwater eutrophication and also comprise an economic burden in terms of lost agricultural production. More intense precipitation events caused by climate change will likely aggravate this problem. So far it is unresolved to which extent soil biota can make ecosystems more resilient to climate change and reduce nutrient leaching losses when rainfall intensity increases. In this study, we focused on arbuscular mycorrhizal (AM) fungi, common soil fungi that form symbiotic associations with most land plants and which increase plant nutrient uptake. We hypothesized that AM fungi mitigate nutrient losses following intensive precipitation events (higher amount of precipitation and rain events frequency). To test this, we manipulated the presence of AM fungi in model grassland communities subjected to two rainfall scenarios: moderate and high rainfall intensity. The total amount of nutrients lost through leaching increased substantially with higher rainfall intensity. The presence of AM fungi reduced phosphorus losses by 50% under both rainfall scenarios and nitrogen losses by 40% under high rainfall intensity. Thus, the presence of AM fungi enhanced the nutrient interception ability of soils, and AM fungi reduced the nutrient leaching risk when rainfall intensity increases. These findings are especially relevant in areas with high rainfall intensity (e.g., such as the tropics) and for ecosystems that will experience increased rainfall due to climate change. Overall, this work demonstrates that soil biota such as AM fungi can enhance ecosystem resilience and reduce the negative impact of increased precipitation on nutrient losses.

Most tree species predominantly associate with a single type of mycorrhizal fungi, which can differentially affect plant nutrient acquisition and biogeochemical cycling. Uncertainties in mycorrhizal distributions are non‐trivial, and current estimates disagree in up to 50% over 40% of the land area, including tropical forests. Remote sensing capabilities for mycorrhizal detection show promise for refining these estimates further. Here, we address for the first time the impact of mycorrhizal distributions on global carbon and nutrient cycling. Using the state‐of‐the‐art carbon‐nitrogen economics within the Community Land Model version 5, we found Net Primary Productivity (NPP) increased throughout the 21st century by 20%; however, as soil nitrogen has progressively become limiting, the costs to NPP for nitrogen acquisition—that is, to mycorrhizae—have increased at a faster rate by 60%. This suggests that nutrient acquisition will increasingly demand a higher portion of assimilated carbon to support the same productivity.

… Emerging evidence suggests that distinct AMF phylogeny exhibit varying soil organic matter mobilization and symbiotic nutrient exchange abilities owing to their divergent life histories. …

… plant-fungal symbioses respond to global change conditions. … –fungal symbioses to global change. Notably, the effects of … Because the general response for mycorrhizal symbioses …

Arbuscular mycorrhizal (AM) symbioses are a potentially important link in the chain of response of ecosystems to elevated atmospheric [CO2]. By promoting plant phosphorus uptake and acting as a sink for plant carbon, they can alleviate photosynthetic down‐regulation. Because hyphal turnover is likely to be fast, especially in warmer soils, they can also act as a rapid pathway for the return of carbon to the atmosphere. However, most experiments on AM responses to [CO2] have failed to take into account the difference in growth of mycorrhizal and non‐ mycorrhizal plants; those that have done so suggest that AM colonization of roots is little altered by [CO2], although this issue remains to be resolved. Very little is known about the effects of other factors of global environmental change on mycorrhizas. These issues need urgent attention. It is also necessary to understand the potential for the various AM fungal taxa to respond differentially to environmental changes, including carbon supply and soil temperature and moisture, especially because of the differential abilities of plant and fungal species to migrate in response to changing environments. Indeed, there is a need for a new approach to the study of mycorrhizal associations, which has been too plant‐centred. It is essential to regard the fungus as an organism itself, and to understand its biology both as an entity and as part of a symbiosis.

… How mycorrhizas … mycorrhizal functioning might impact future soil-plant nutrition. C:N:phosphorus (P) ratios provide useful insights into processes such as photosynthesis, nutrient uptake…

… Under experimental conditions where plants are grown in presence of one particular AM fungal isolate, the net outcome of the mycorrhizal symbiosis in terms of plant nutrient uptake not …

Land plants play a key role in global carbon cycling, but the potential role of arbuscular mycorrhizal fungi (AMF) in the responses of a wide range of plant species to global change factors (GCFs) remains limited. Based on 1100 paired observations from 181 plant species, we conducted a meta-analysis to test the role of AMF in plant responses to four GCFs: drought, warming, nitrogen (N) addition and elevated CO2 . We show that AMF significantly ameliorate the negative effects of drought on plant performance. The GCFs N addition and elevated CO2 significantly enhance the performance of AM plants but not of non-inoculated plants. AM plants show better performance than their non-inoculated counterparts under warming, although neither of them showed a significant response to this GCF. These results suggest that AMF benefit plants in response to GCFs. Our study highlights the importance of AMF in enhancing plant performance under ongoing global change.

Global climate changes have serious consequences on natural ecosystems and cause diverse environmental abiotic stressors that negatively affect plant growth and development. Trees are dependent on their symbiosis with mycorrhizal fungi, as the hyphal network significantly improves the uptake of water and essential mineral nutrients by colonized roots. A number of recent studies has enhanced our knowledge on the functions of mycorrhizal associations between fungi and plant roots. Moreover, a series of timely studies have investigated the impact and benefit of root symbioses on the adaptation of plants to climate change-associated stressors. Trees in temperate and boreal forests are increasingly exposed to adverse environmental conditions, thus affecting their durable growth. In this mini-review, we focus our attention on the role mycorrhizal symbioses play in attenuating abiotic stressors imposed on trees facing climatic changes, such as high temperatures, drought, salinity, and flooding.

Arbuscular mycorrhizal (AM) fungi are amongst the most common and functionally important symbionts of terrestrial plants and are highly likely to be affected by global change. The potential consequences of this on plant growth and carbon and nutrient cycling has led to a growing demand for their inclusion in global change models. However, our understanding of their responses to environmental change remains limited. This review provides an overview of recent experiments attempting to predict the effects of atmospheric and climatic change on AM fungal community diversity, composition and functioning. This includes rising atmospheric carbon dioxide and tropospheric ozone levels, altered water availability, warming and nitrogen deposition. Changes detected are often highly variable and context dependent, but trends are emerging such as the similar responses of community composition to enhanced nitrogen deposition and atmospheric CO2, despite the likely contrasting effects of these environmental changes on carbon availability. The review also highlights shortfalls in our current knowledge and suggests priorities for future research, particularly advocating more integrated approaches linking the study of community characteristics and functions and examination of fine level genetic changes, wider geographical contexts and a greater range of AM fungal functions.

… global changes, and their applications for ecosystem sustainability. This chapter provides a historical overview of mycorrhizal symbiosis … mechanisms underlying nutrient uptake and …

… The root systems of most land plants form AM symbioses, which contribute to plant nutrient uptake. There have been recent breakthroughs in our understanding of the common …

Chapter 5 Mycorrhizal Symbiosis and Nutrients Uptake in Plants Kashif Tanwir, Kashif Tanwir Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this authorSaghir Abbas, Saghir Abbas Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this authorMuhammad Shahid, Muhammad Shahid Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, PakistanSearch for more papers by this authorHassan Javed Chaudhary, Hassan Javed Chaudhary Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PakistanSearch for more papers by this authorMuhammad Tariq Javed, Muhammad Tariq Javed Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this author Kashif Tanwir, Kashif Tanwir Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this authorSaghir Abbas, Saghir Abbas Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this authorMuhammad Shahid, Muhammad Shahid Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, PakistanSearch for more papers by this authorHassan Javed Chaudhary, Hassan Javed Chaudhary Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PakistanSearch for more papers by this authorMuhammad Tariq Javed, Muhammad Tariq Javed Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, PakistanSearch for more papers by this author Book Editor(s):Vijay Pratap Singh, Vijay Pratap Singh University of Allahabad, Prayagraj, IndiaSearch for more papers by this authorManzer H. Siddiqui, Manzer H. Siddiqui King Saud University, Riyadh, Saudi ArabiaSearch for more papers by this author First published: 03 March 2023 https://doi.org/10.1002/9781119803041.ch5 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onEmailFacebookTwitterLinkedInRedditWechat Summary The roots of terrestrial plants establish arbuscular mycorrhizal associations with root residing fungal species. These associations increased nutrients accumulation in plants and played a vital role in their metabolism and growth. These fungal associations enhanced the plants nutrients accumulation efficiency by increasing the nutrient absorption area of plant roots. In return, these symbiotic fungi take carbohydrates as a source of food and shelter from plant roots. These fungal symbioses are not associated with plant diseases; however, these often contribute to overcome abiotic and biotic stresses through enhancing nutrient supply. These symbiotic fungi can endorse the nutrients uptake from water and soil by host plants. The chief mechanisms behind the mycorrhizal decomposition of soil organic matter generally comprise enzymatic degradation, priming effects, and nonenzymatic mechanism like Fenton chemistry, which in response encourage N and C cycling. Moreover, these symbiotic relationships between plant roots and fungi are capable of releasing phosphatases and organic acids to enhance the solubility of phosphorous (P) in soil and mycelium growth, which enable plants to acquire more P. However, the growth of fungal community is regulated by numerous environmental factors including host distribution, soil conditions, and climatic changes. Due to enhanced nutrients accumulation capacity of arbuscular mycorrhizal fungi, these are known as biofertilizers. So the current chapter focuses on various mechanisms adopted by mycorrhizal fungi for enhancing plant nutrition, their applications, and advantages. 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Mycorrhiza : – . , ( ). of mycorrhizal inoculation on phosphorus sustainability in and in the in . J. Plant 26 : 1 – . , ( 2012 ). maize and plants on in of phosphorus and uptake . J. Plant : – . , , , , and , ( ). uptake of phosphorus by mycorrhizal plants as by of nitrogen . Plant Soil : – . , and , M. ( 2017 ). The mechanisms of nutrient uptake by arbuscular . In: Uptake, Biocontrol, Ecorestoration , 1 – . Cham : Springer . , , , N. , , C. , and , H. ( 2013 ). of arbuscular mycorrhizal fungi for growth, mycorrhizal and nutrient uptake . J. Sci. : – . Pozo , M.J. , , J.A. , , C. , and , J.M. ( 2015 ). as of environmental signals in the regulation of mycorrhizal symbioses . New Phytol. : 1431 – . Prasad , R. , , D. , , K. et al. ( 2017 ). to development . In: Mycorrhiza (ed. A. Varma , R. Prasad and N. Tuteja ), 1 – 7 . Cham : Springer . , S. , Bidartondo , M.I. , Field , K.J. et al. ( 2016 ). fungal current knowledge and . J. Syst. Evol. ( 6 ): – . , , , , , M. , and , S.D. 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( 2018 ). changes in root growth and nutrient absorption of plants . Plant Soil Environ. : – . , D. , , M. , , et al. ( 2013 ). The arbuscular mycorrhizal symbiosis influences sulfur starvation of Medicago truncatula . New Phytol. : – . , M. and , S. ( ). of simulated phosphorus uptake to by a model . Plant Soil : – . Singh , S. , , K. , , J. et al. ( 2014 ). a symbiotic root development . Cell 15 : – . Smith , S. and , D. ( ). Mycorrhizal Symbiosis , . : . Smith , S.E. and , ( 2010 ). Mycorrhizal Symbiosis . : Academic . Smith , S.E. and Smith , ( 2011 ). Roles of arbuscular mycorrhizas in plant nutrition and from to . Annu. Rev. Plant Biol. : – . Smith , S.E. , Smith , , and , ( ). Functional diversity in arbuscular mycorrhizal the of the mycorrhizal uptake is not with mycorrhizal in growth or uptake . New Phytol. : – . , M. and , M. ( ). Phosphate from of in and for phosphorus translocation . New Phytol. : – . , , , , , et al. ( 2010 ). plant of plants through mycorrhizal . 5 ( 10 ): . , M.A. , , , , R. , and , M.C. ( 2019 ). arbuscular mycorrhizal fungi for sustainability and a under Front. Microbiol. 10 : . Strullu-Derrien , C. , , P. , , S. et al. ( 2014 ). Fungal associations in from the C in plants: plant–fungus symbioses . New Phytol. ( 3 ): – . , and , ( 2020 ). in of the mechanisms of carbon and nitrogen exchange in ectomycorrhizal symbioses . Front. Plant Sci. 10 : . , Y. and , K. ( 2005 ). Nitrogen to maize mycorrhizal depends on the of N . Plant Cell Environ. : – . , N. , , H. , , S. et al. ( 2016 ). A of the gene of Glomeromycota for . Front. Microbiol. 7 : . Tanwir , K. , , , Masood , S. et al. ( 2015 ). dynamics nutrient and physiological of maize ( . Environ. Sci. ( 12 ): – . Tanwir , K. , Javed , M.T. , Abbas , S. et al. ( ). sp. alleviates Cd toxicity by and Cd uptake in L. cultivars in Cd tolerance . Environ. : . Tedersoo , L. and Brundrett , M.C. ( 2017 ). of ectomycorrhizal symbiosis in plants . In: of Mycorrhizal Symbiosis (ed. L. Tedersoo ), – . Cham : Springer . , E. , , A. , , P. et al. ( 2012 ). The of the arbuscular mycorrhizal fungus Glomus intraradices functional in an . New ( 3 ): – . , E. , , M. , , A. et al. ( 2013 ). Genome of an arbuscular mycorrhizal fungus the plant symbiosis . Proc. Natl. Acad. Sci. U. S. A. : – . , M. , , G. , , P. et al. ( 2005 ). of fungi on their plant host for . Appl. Environ. Microbiol. 71 : – . , , , , , M.A. , and , ( 2015 ). Mycorrhizal and the the and the . New Phytol. ( 4 ): – . , N. , , P.E. , and , ( ). Phosphate dynamics in the arbuscular mycorrhizal fungus Glomus intraradices by in . New Phytol. : – . , , , , , P. et al. ( 2010 ). strigolactone and formation in . Plant J. : – 311 . , , , J. , , et al. ( 2017 ). Nutrient exchange and regulation in arbuscular mycorrhizal symbiosis . Mol. Plant 10 : – . , H. ( ). and transport in to phosphorus and and the regulation of mycorrhizal associations . of a , University of , . , , , H. , , et al. ( 2016 ). Arbuscular mycorrhizal symbiosis a phosphate in the fungal . Mol. Plant : – . , A. , , , , et al. ( 1995 ). for and morphology in yeast . Mol. Biol. Cell 6 ( 5 ): – . , K. , , , , H. et al. ( 2012 ). nitrogen and phosphorus strigolactone production and Planta 235 : – . , F. , , M. , , et al. ( 2013 ). of formation on the phosphorus and uptake of . Commun. Soil Sci. Plant 44 : – 1352 . , F. , , , , , and , K. ( 2020 ). Arbuscular mycorrhizas root metabolism to enhance tolerance of . Environ. : . Plant and

Mycorrhizal symbioses between plants and fungi are vital for the soil structure, nutrient cycling, plant diversity, and ecosystem sustainability. More than 250 000 plant species are associated with mycorrhizal fungi. Recent advances in genomics and related approaches have revolutionized our understanding of the biology and ecology of mycorrhizal associations. The genomes of 250+ mycorrhizal fungi have been released and hundreds of genes that play pivotal roles in regulating symbiosis development and metabolism have been characterized. rDNA metabarcoding and metatranscriptomics provide novel insights into the ecological cues driving mycorrhizal communities and functions expressed by these associations, linking genes to ecological traits such as nutrient acquisition and soil organic matter decomposition. Here, we review genomic studies that have revealed genes involved in nutrient uptake and symbiosis development, and discuss adaptations that are fundamental to the evolution of mycorrhizal lifestyles. We also evaluated the ecosystem services provided by mycorrhizal networks and discuss how mycorrhizal symbioses hold promise for sustainable agriculture and forestry by enhancing nutrient acquisition and stress tolerance. Overall, unraveling the intricate dynamics of mycorrhizal symbioses is paramount for promoting ecological sustainability and addressing current pressing environmental concerns. This review ends with major frontiers for further research.

Climate change is likely to have severe impacts on food security in the topics as these regions of the world have both the highest human populations and narrower climatic niches, which reduce the diversity of suitable crops. Legume crops are of particular importance to food security, supplying dietary protein for humans both directly and in their use for feed and forage. Other than the rhizobia associated with legumes, soil microbes, in particular arbuscular mycorrhizal fungi (AMF), can mitigate the effects of biotic and abiotic stresses, offering an important complementary measure to protect crop yields. This review presents current knowledge on AMF, highlights their beneficial role, and explores the potential for application of AMF in mitigating abiotic and biotic challenges for tropical legumes. Due to the relatively little study on tropical legume species compared to their temperate growing counterparts, much further research is needed to determine how similar AMF–plant interactions are in tropical legumes, which AMF species are optimal for agricultural deployment and especially to identify anaerobic AMF species that could be used to mitigate flood stress in tropical legume crop farming. These opportunities for research also require international cooperation and support, to realize the promise of tropical legume crops to contribute to future food security.

… Under elevated CO 2 , nearly all nutrient elements tended to … to CO 2 , elevated ozone tended to increase tuber nutrient element … on nutrient element decrease. Thus, the total amount of …

Ozone (O3) levels on Earth are increasing because of anthropogenic activities and natural processes. Ozone enters plants through the leaves, leading to the overgeneration of reactive oxygen species (ROS) in the mesophyll and guard cell walls. ROS can damage chloroplast ultrastructure and block photosynthetic electron transport. Ozone can lead to stomatal closure and alter stomatal conductance, thereby hindering carbon dioxide (CO2) fixation. Ozone-induced leaf chlorosis is common. All of these factors lead to a reduction in photosynthesis under O3 stress. Long-term exposure to high concentrations of O3 disrupts plant physiological processes, including water and nutrient uptake, respiration, and translocation of assimilates and metabolites. As a result, plant growth and reproductive performance are negatively affected. Thus, reduction in crop yield and deterioration of crop quality are the greatest effects of O3 stress on plants. Increased rates of hydrogen peroxide accumulation, lipid peroxidation, and ion leakage are the common indicators of oxidative damage in plants exposed to O3 stress. Ozone disrupts the antioxidant defense system of plants by disturbing enzymatic activity and non-enzymatic antioxidant content. Improving photosynthetic pathways, various physiological processes, antioxidant defense, and phytohormone regulation, which can be achieved through various approaches, have been reported as vital strategies for improving O3 stress tolerance in plants. In plants, O3 stress can be mitigated in several ways. However, improvements in crop management practices, CO2 fertilization, using chemical elicitors, nutrient management, and the selection of tolerant crop varieties have been documented to mitigate O3 stress in different plant species. In this review, the responses of O3-exposed plants are summarized, and different mitigation strategies to decrease O3 stress-induced damage and crop losses are discussed. Further research should be conducted to determine methods to mitigate crop loss, enhance plant antioxidant defenses, modify physiological characteristics, and apply protectants.

… on internal nutrient recycling as a compensatory mechanism. … of elevated O 3 on nutrient resorption proficiency (ie, the final … of nutrient uptake would be necessary to fully confirm this …

… The aim of this open-air fumigation study is to look at the possible interactions between low level ozone exposure and the nutrient deficiency of conifers, to obtain basic information …

… Elevated ozone increased both N and P concentrations of … On these variables, ozone had a greater effect for clone 546 than for … processes, which increased under elevated ozone. N …

… of ozone (O 3 ) on uptake and utilization of nitrogen, phosphorus, and potassium nutrients in … Two hybrid indica cultivars were exposed to ambient and elevated O 3 (EO 3 ) under a free-…

Ground-level ozone (O3) is a secondary air pollutant and affects the roots and soil processes of trees. Therefore, O3 can affect the uptake and allocation of nutrients in trees, which merits further clarification. A fumigation experiment with five O3 levels was conducted in 15 open top chambers for two poplar clones, and the concentrations of six macronutrients (N, P, K, S, Ca, Mg) in different organs and leaf positions were determined. Under all O3 levels, the concentration of mobile nutrients (N and P) was higher in upper leaves than in lower leaves, while the non-mobile nutrients (Ca and S) concentration was the opposite. Relative to charcoal filtered ambient air (CF), high O3 treatment (NF60) significantly increased the concentration of mobile nutrients K and Mg in upper leaves by 38 % and 33 %, in lower leaves by 142 % and 65 %, respectively, which suggested the effect of O3 on their concentrations was greater at the lower leaf position than at the upper leaf position. Elevated O3 significantly increased the macronutrient concentrations in most organs. The effects of O3 on nutrient concentrations were attributed using graphical vector analysis, suggested that the increase of nutrient concentration in the shoots was attributed to excessive nutrient stocks, while their increase in root was attributed to the "concentration" effect. Compared to CF, NF60 also reduced the root-to-shoot ratio of N, P, S, K, Ca and Mg stocks by 34 %, 39 %, 37 %, 64 %, 46 % and 42 %, respectively, indicating the allocation of increased nutrients to shoots in response to O3 stress. Changes in the allocation pattern of nutrients in different leaf positions and organs of poplar were primarily in response to O3 stress since these nutrients play important roles in some physiological processes. These results will help improve the plantation nutrient utilization by optimizing fertilizer management regimes under O3 pollution.

Wang Y.B., Wei S.Y., Sun Y., Mao W., Dang T.T., Yin W.Q., Wang S.S., Wang X.Z. (2017): Elevated ozone level affects micronutrients bioavailability in soil and their concentrations in wheat tissues. Plant Soil Environ., 63: 381–387. To investigate the bioavailability of essential micronutrients (Fe, Mn, Cu, Zn) in soil-plant system, sequential scheme of weak acid soluble (WAS), reducible (RED) and oxidizable (OXI) fractions was used to evaluate the bioavailability of micronutrients in different soil depths. The results revealed that at the tillering stage elevated O3 concentration significantly increased WAS-Fe at 0–5 cm and 10–15 cm soils by 69.11% and 59.72%, respectively. At the ripening stage, both WAS-Cu and RED-Cu were significantly increased in elevated O3 treatment compared to control, while WAS-Mn only showed significant in 0–5 cm soil. In bulk soil, WAS-Zn and RED-Zn concentrations were generally greater than those in control, which was more evident at 10–15 cm soil. Besides, O3 decreased the whole plant biomass by 14.63% and increased the root to shoot ratio. Elevated O3 significantly increased grain Fe, Mn and Cu concentrations by 9.37, 36.68 and 48.18%, respectively, while it decreased Zn by 17.09%. It can be inferred that altered micronutrients bioavailability in soil and nutrients uptake in plants are likely associated with the changed soil chemical properties and plant physiology in response to the rising O3 level.

Tropospheric ozone (O3 ) is an important stressor in natural ecosystems, with well-documented impacts on soils, biota and ecological processes. The effects of O3 on individual plants and processes scale up through the ecosystem through effects on carbon, nutrient and hydrologic dynamics. Ozone effects on individual species and their associated microflora and fauna cascade through the ecosystem to the landscape level. Systematic injury surveys demonstrate that foliar injury occurs on sensitive species throughout the globe. However, deleterious impacts on plant carbon, water and nutrient balance can also occur without visible injury. Because sensitivity to O3 may follow coarse physiognomic plant classes (in general, herbaceous crops are more sensitive than deciduous woody plants, grasses and conifers), the task still remains to use stomatal O3 uptake to assess class and species' sensitivity. Investigations of the radial growth of mature trees, in combination with data from many controlled studies with seedlings, suggest that ambient O3 reduces growth of mature trees in some locations. Models based on tree physiology and forest stand dynamics suggest that modest effects of O3 on growth may accumulate over time, other stresses (prolonged drought, excess nitrogen deposition) may exacerbate the direct effects of O3 on tree growth, and competitive interactions among species may be altered. Ozone exposure over decades may be altering the species composition of forests currently, and as fossil fuel combustion products generate more O3 than deteriorates in the atmosphere, into the future as well.

Tropospheric ozone is a major air pollutant in industrialized countries. It is formed by photochemical oxidation of primary pollutants released into the air by burning of fossil fuels. In the presence of high irradiance the generation of ozone (O3) is initiated by nitrogen dioxide (NO2) and driven by volatile hydrocarbons and other components present in exhaust from traffic, power plants, or industrial productions.1 Ozone is also a natural component in air at low concentrations of 5 to 15 ppb.2 However, during the last 100 years these background levels have approximately doubled. Under clear and sunny weather conditions, O3 rises to peak levels and occasionally reaches concentrations above 120 ppb.1

We tested the independent and interactive effects of nitrogen (N; 0 and 80 kg ha-1), phosphorus (P; 0, 40 and 80 kg ha-1), and ozone (O3) application/exposure [ambient concentration (AA), 1.5 × AA and 2.0 × AA] for five consecutive months on biochemical traits of the O3-sensitive Oxford poplar clone. Plants exposed to O3 showed visible injury and an alteration of membrane integrity, as confirmed by the malondialdehyde by-product accumulation (+3 and +17% under 1.5 × AA and 2.0 × AA conditions, in comparison to AA). This was probably due to O3-induced oxidative damage, as documented by the production of superoxide anion radical (O2-, +27 and +63%, respectively). Ozone per se, independently from the concentrations, induced multiple signals (e.g., alteration of cellular redox state, increase of abscisic acid/indole-3-acetic acid ratio and reduction of proline content) that might be part of premature leaf senescence processes. By contrast, nutrient fertilization (both N and P) reduced reactive oxygen species accumulation (as confirmed by the decreased O2- and hydrogen peroxide content), resulting in enhanced membrane stability. This was probably due to the simultaneous involvement of antioxidant compounds (e.g., carotenoids, ascorbate and glutathione) and osmoprotectants (e.g., proline) that regulate the detoxification processes of coping with oxidative stress by reducing the O3 sensitivity of Oxford clone. These mitigation effects were effective only under AA and 1.5 × AA conditions. Nitrogen and P supply activated a free radical scavenging system that was not able to delay leaf senescence and mitigate the adverse effects of a general peroxidation due to the highest O3 concentrations.

The effects of increasing ambient ozone (O3) concentrations on food security has become a major concern as the demand for agricultural productivity is projected to increase significantly over the next several decades. In this contribution, the responses of common soybean genotypes (AK-HARROW, PI88788, DWIGHT, PANA, and WILLIAMS82) to ambient O3 are characterized using hyperspectral data and foliar biophysical, mineral nutrient concentrations and soybean yield. Specifically, leaf reflectance spectra measured at different growth stages and canopy layers were used to examine the spectral indices that were most strongly correlated with leaf physiological status. The effects of elevated O3 on six important nutrients (K, Ca, Mg, Fe, Mn and Cu) were evaluated by analyzing the variations in nutrient concentrations at two critical growth stages with increasing ambient O3 concentration using Partial Least Square Regression (PLSR). Lastly, the identified best spectral indices and the robust nutrient prediction models were extrapolated to the entire growth period to explore their ability to track the effects of ambient O3 concentrations on soybean physiology and nutrient uptake. The results showed that fluorescence yield (ΔF/Fm’) and photochemical quenching (qP) appear to be good indicators of soybean physiological responses to O3 stress that are echoed by the harvest index (HI). Newly identified normalized difference spectral index (NDSI) [R416, R2371] always had the highest correlation (R2 > 0.6) with ΔF/Fm’, qP and electron transport rate (ETR, μmol m−2 s−1) compared to the published indices. Additionally, there were significant and broad spectral regions in visible and near infrared region that were well-correlated with ΔF/Fm’ and selected NDSIs that were applicable to satellite observations. The results of nutrient modeling using PLSR explained 54–87% of the variance in nutrient concentrations, and the predicted mineral nutrient accumulation throughout the growing season reflected the responses of ozone tolerant and sensitive genotypes well. NDSI [R416, R2371] demonstrated great potential in regard to its sensitivity in tracking plant physiological responses to changing ambient O3 concentrations. The outcome of this research has potential implications for development of space-based observation of large-scale crop responses to O3 damage, as well as for biotechnological breeding efforts to improve ozone tolerance under future climate scenarios.

Ozone (O3), a widespread air pollutant, significantly impairs crop growth and development, with wheat, the second largest crop by planting area of the world, being especially vulnerable. This study, conducted under Free Air Concentration Enrichment (FACE) conditions, focused on four wheat cultivars from the middle and lower reaches of the Yangtze River, investigating the effects of elevated O3 on wheat growth, physiology and quality.

… high ozone level {P = 0-04) relative to the subambient ozone … ozone stress effectively results in lower pollutant uptake and … mechanism in foliage produced under chronic ozone stress. In …

… a mechanism to respond to changes in available resources such as nitrogen (N). Increased N uptake … The authors attributed increased root respiration to increased nutrient uptake in …

Unprecedented bioaccumulation and biomagnification of heavy metals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants.

… , but decreases in response to elevated temperature and heavy metal stresses (Upchurch … Different types of abiotic stresses, such as nutrient deficiency, drought, UV-B radiation, and …

… with fertilizer application. This supported the assumption that a major nutrient deficiency, paticularly of P, rather than metal toxicity, limited plant growth at the studied serpentine site. …

Abstract Knowledge of plant aboveground and belowground biomass (AGB and BGB) allocation is fundamental for our understanding of terrestrial carbon sequestration in a changing climate. However, how multiple global change factors interactively affect biomass allocation in terrestrial ecosystems remains unclear. We used meta-analysis to synthesize main and interactive effects of global change factors on AGB, BGB, and root/shoot based on 129 multiple-factor studies. Elevated CO2 (E), nitrogen addition (N), warming (W), irrigation (I) and their combinations (EN, EW, NW, ENW, IE, IN, IW, IEN, INW and IENW) significantly increased AGB. However only half of the treatments (i.e., E, N, W, EN, EW, NW, IE and IW) stimulated BGB, leading to significant declines of root/shoot in treatments with I and/or N. Drought (D) significantly decreased both total biomass (14%) and AGB (47%), but increased root/shoot by 21% as well as DE and DW. Additive interactions between global change factors exhibited a predominance on both plant biomass (69.0%) and biomass allocation (64.8%). The proportion of synergistic interaction in AGB’s responses to multiple global change factors was greater relative to that in BGB. Response correlation between AGB and root/shoot was observed in woody plants, while, in herbaceous ones, we found the correlation between BGB and root/shoot. Our findings highlight the importance of the interactive effects among global change factors on biomass allocation. Incorporating these interactions into global vegetation models may improve predictions of future global carbon storage and could inform sustainable strategies for grassland and plantation management in a future climate.

Plant functional traits are a representation of plant resource utilization strategies. Plants with higher specific leaf area (SLA) and lower leaf dry matter content (LDMC) exhibit faster investment-return resource utilization strategies. However, the distribution patterns and driving factors of plant resource utilization strategies at the macroscale are rarely studied. We investigated the relative importance of climatic and soil factors in shaping plant resource utilization strategies at different life forms in forests using data collected from 926 plots across 163 forests in China. SLA and LDMC of plants at different life forms (i.e., trees, shrubs, and herbs) differ significantly. Resource utilization strategies show significant geographical differences, with vegetation in the western arid regions adopting a slower investment-return survival strategy and vegetation in warmer and wetter areas adopting a faster investment-return survival strategy. SLA decreases significantly with increased temperature and reduced rainfall, and vegetation growing in these conditions exhibits conservative resource utilization. Mean annual precipitation (MAP) is a key climatic factor that controls the resource utilization strategies of plants at the macroscale. Plants use resources more conservatively as soil pH increases. The influence of climate and soil factors is coupled to determine the resource utilization strategies of plants occupying different life forms at the macroscale, but the relative contribution of each varies across life forms. Our findings provide a theoretical framework for understanding the potential impact of increasing global temperatures on plant resource utilization.

… long-term, multi-factor field manipulations, … resource addition than plants that have high root-to-shoot ratios. Other tradeoffs in physiology or allocation may play a role in resource strategy…

Significance Accurate prediction of community responses to global change drivers (GCDs) is critical given the effects of biodiversity on ecosystem services. There is consensus that human activities are driving species extinctions at the global scale, but debate remains over whether GCDs are systematically altering local communities worldwide. Across 105 experiments that included over 400 experimental manipulations, we found evidence for a lagged response of herbaceous plant communities to GCDs caused by shifts in the identities and relative abundances of species, often without a corresponding difference in species richness. These results provide evidence that community responses are pervasive across a wide variety of GCDs on long-term temporal scales and that these responses increase in strength when multiple GCDs are simultaneously imposed. Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.

Plant stoichiometric coupling among all elements is fundamental to maintaining growth-related ecosystem functions. However, our understanding of nutrient balance in response to global changes remains greatly limited to plant carbon : nitrogen : phosphorus (C : N : P) coupling. Here we evaluated nine element stoichiometric variations with one meta-analysis of 112 global change experiments conducted across global terrestrial ecosystems and one synthesis over 1900 species observations along natural environment gradients across China. We found that experimentally increased soil N and P respectively enhanced plant N : potassium (K), N : calcium (Ca) and N : magnesium (Mg), and P : K, P : Ca and P : Mg, and natural increases in soil N and P resulted in qualitatively similar responses. The ratios of N and P to base cations decreased both under experimental warming and with naturally increasing temperature. With decreasing precipitation, these ratios increased in experiments but decreased under natural environments. Based on these results, we propose a new stoichiometric framework in which all plant element contents and their coupling are not only affected by soil nutrient availability, but also by plant nutrient demand to maintain diverse functions under climate change. This study offers new insights into understanding plant stoichiometric variations across a full set of mineral elements under global changes.

… Wetland plant biomass and its allocation are sensitive to environmental changes, and they … Here, we collected global data on wetland plant biomass from 1980 to 2021. Based on an …

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits often used to reflect plant resource utilization strategies and predict plant responses to environmental changes. In general, grassland plants at different elevations exhibit varying survival strategies. However, it remains unclear how grassland plants adapt to changes in elevation and their driving factors. To address this issue, we utilized SLA and LDMC data of grassland plants from 223 study sites at different elevations in China, along with climate and soil data, to investigate variations in resource utilization strategies of grassland plants along different elevational gradients and their dominant influencing factors employing linear mixed-effects models, variance partitioning method, piecewise Structural Equation Modeling, etc. The results show that with increasing elevation, SLA significantly decreases, and LDMC significantly increases (P < 0.001). This indicates different resource utilization strategies of grassland plants across elevation gradients, transitioning from a “faster investment-return” at lower elevations to a “slower investment-return” at higher elevations. Across different elevation gradients, climatic factors are the main factors affecting grassland plant resource utilization strategies, with soil nutrient factors also playing a non-negligible coordinating role. Among these, mean annual precipitation and hottest month mean temperature are key climatic factors influencing SLA of grassland plants, explaining 28.94% and 23.88% of SLA variation, respectively. The key factors affecting LDMC of grassland plants are mainly hottest month mean temperature and soil phosphorus content, with relative importance of 24.24% and 20.27%, respectively. Additionally, the direct effect of elevation on grassland plant resource utilization strategies is greater than its indirect effect (through influencing climatic and soil nutrient factors). These findings emphasize the substantive impact of elevation on grassland plant resource utilization strategies and have important ecological value for grassland management and protection under global change.

The stoichiometry and allometry of nitrogen (N) and phosphorus (P) reflect nutrient absorption and dynamic allocation by plants, and can be regulated by global change factors (e.g. nitrogen enrichment, climate warming and altered precipitation). Yet, how multiple global change factors act interactively to influence the stoichiometric characteristics of N and P and their scaling relationships in different plant organs remains poorly understood. In a field experiment with treatments of nitrogen addition (Nadd), warming (W) and reduced precipitation (Pr) in an alpine meadow, we examined how global change factors interact to alter N and P stoichiometric characteristics of leaves and seeds. An allometry model (i.e. N = βPα) was employed to detect changes in the scaling of plant N to P under different treatments. Our results showed that nitrogen addition significantly increased leaf N concentration (+44.0%), seed N concentration (+16.9%) and leaf N:P ratios (+27.8%) under ambient temperatures and significantly increased leaf N concentration (+53.7%) and leaf N:P ratios (+46.4%) under ambient precipitation. Importantly, nitrogen addition and warming (or reduced precipitation) had synergistic effects on P concentration of leaves and seeds, and antagonistic effects on N:P ratios of leaves. Moreover, although none of the three global change factors individually altered the scaling of N to P, nitrogen addition interacted with warming or with reduced precipitation to decrease the scaling exponents in leaves and increase them in seeds. Our results suggest that multiple global change factors can alter the N and P allocation patterns and result in decoupling of N and P in different plant organs. These findings highlight the importance of considering interactions of multiple factors when predicting dynamic changes in plant stoichiometric characteristics and nutrient utilization strategies under global change scenarios. Read the free Plain Language Summary for this article on the Journal blog.

… by changes in the resource-use strategies of the plant species … Multifactorial experiments have demonstrated that plant … atmospheric CO 2 or climate change (reviewed in Bardgett & …

The activities of extracellular enzymes, the proximate agents of decomposition in soils, are known to depend strongly on temperature, but less is known about how they respond to changes in precipitation patterns, and the interaction of these two components of climate change. Both enzyme production and turnover can be affected by changes in temperature and soil moisture, thus it is difficult to predict how enzyme pool size may respond to altered climate. Soils from the Boston-Area Climate Experiment (BACE), which is located in an old field (on abandoned farmland), were used to examine how climate variables affect enzyme activities and microbial biomass carbon (MBC) in different seasons and in soils exposed to a combination of three levels of precipitation treatments (ambient, 150% of ambient during growing season, and 50% of ambient year-round) and four levels of warming treatments (unwarmed to ~4°C above ambient) over the course of a year. Warming, precipitation and season had very little effect on potential enzyme activity. Most models assume that enzyme dynamics follow microbial biomass, because enzyme production should be directly controlled by the size and activity of microbial biomass. We observed differences among seasons and treatments in mass-specific potential enzyme activity, suggesting that this assumption is invalid. In June 2009, mass-specific potential enzyme activity, using chloroform fumigation-extraction MBC, increased with temperature, peaking under medium warming and then declining under the highest warming. This finding suggests that either enzyme production increased with temperature or turnover rates decreased. Increased maintenance costs associated with warming may have resulted in increased mass-specific enzyme activities due to increased nutrient demand. Our research suggests that allocation of resources to enzyme production could be affected by climate-induced changes in microbial efficiency and maintenance costs.

Many factors influence global change Global environmental change is driven by multiple natural and anthropogenic factors. With a focus on global change as it affects soils, Rillig et al. point out that nearly all published studies consider just one or two factors at a time (see the Perspective by Manning). In a laboratory experiment, they tested 10 drivers of global change both individually and in combination, at levels ranging from 2 to 10 factors. They found that soil properties, processes, and microbial communities could not be predicted from single-effect responses and that multiple factors in combination produced unsuspected responses. They concluded that single-factor studies remain important for uncovering mechanisms but that global change biology needs to embrace more fully the multitude of drivers impinging on ecosystems. Science, this issue p. 886; see also p. 801 A combination of global change factors can predict trends of ecosystem reactions, soil properties, and microbial communities. Soils underpin terrestrial ecosystem functions, but they face numerous anthropogenic pressures. Despite their crucial ecological role, we know little about how soils react to more than two environmental factors at a time. Here, we show experimentally that increasing the number of simultaneous global change factors (up to 10) caused increasing directional changes in soil properties, soil processes, and microbial communities, though there was greater uncertainty in predicting the magnitude of change. Our study provides a blueprint for addressing multifactor change with an efficient, broadly applicable experimental design for studying the impacts of global environmental change.

… of realistic multifactorial global changes. We investigated the response of soil bacteria to simulated multifactorial global change as part of the Jasper Ridge Global Change Experiment (…