Changes In Plant Functional Traits Research Articles

Plant Leaf Functional Adaptions along Urban-Rural Gradients of Jinhua City.

Environmental changes induced by urbanization may significantly alter plant survival strategies, thereby introducing uncertainties in their ability to withstand extreme heat. This study, centered on Jinhua City, distinguished urban, suburban, and rural areas to represent the various intensities of urbanization. It examined the leaf function properties of evergreen and deciduous trees common in these regions, focusing on leaf and branch characteristics. Employing an analysis of variance (ANOVA), principal component analysis (PCA), and path analysis (PA) of the plant functional traits and the climatic factors of each region, this study assessed the impact of urbanization on plant survival strategies. By tracking changes in plant functional traits from June to August, it explored the capacity of plants to acclimate to urban-warming-related heat stress across different urbanization gradients. The findings revealed that leaf thickness (LT) and stomatal size (SS) initially decreased and then increased, whereas specific leaf area (SLA) and leaf tissue density (LTD) first rose and then declined, from rural to urban regions. From June to August, branch wood density (WD), chlorophyll (Chl) content, LTD, and leaf dry matter content (LDMC) increased, whereas SLA and leaf water content (LWC) diminished, in all regions. PCA suggested that there was no significant change in the resource allocation strategy of plants (p > 0.05), with drought tolerance significantly reduced in the suburbs on the gradient of urbanization (p < 0.05). During the summer, with high temperature, plants were predominantly biased towards slow-return, conservative strategies, particularly among evergreen species. Compared to precipitation, PA revealed a significant urban warming effect. During summer, temperature was the main factor influencing resource investment strategy and drought resistance, with a notably stronger impact on the former. The high temperature in summer promoted a conservative survival strategy in plants, and the urbanization effect increased their tolerance to high temperatures.

Experimental evidence that root-associated fungi improve plant growth at high altitude.

Unravelling how species communities change along environmental gradients requires a dual understanding: the direct responses of the species to their abiotic surroundings and the indirect variation of these responses through biotic interactions. Here, we focus on the interactive relationships between plants and their symbiotic root-associated fungi (RAF) along stressful abiotic gradients. We investigate whether variations in RAF community composition along altitudinal gradients influence plant growth at high altitudes, where both plants and fungi face harsher abiotic conditions. We established a translocation experiment between pairs of Bistorta vivipara populations across altitudinal gradients. To separate the impact of shifting fungal communities from the overall influence of changing abiotic conditions, we used a root barrier to prevent new colonization by RAF following translocation. To characterize the RAF communities, we applied DNA barcoding to the root samples. Through the utilization of joint species distribution modelling, we assessed the relationship between changes in plant functional traits resulting from experimental treatments and the corresponding changes in the RAF communities. Our findings indicate that RAF communities influence plant responses to stressful abiotic conditions. Plants translocated from low to high altitudes grew more when they were able to associate with the resident high-altitude RAF compared to those plants that were not allowed to associate with the resident RAF. We conclude that interactions with RAF impact how plants respond to stressful abiotic conditions. Our results provide experimental support that interactions with RAF improve plant stress tolerance to altitudinal stressors such as colder temperatures and less nutrient availability.

Invasive earthworms modulate native plant trait expression and competition

Biological invasions have major impacts on a variety of ecosystems and threaten native biodiversity. Earthworms have been absent from northern parts of North America since the last ice age, but non‐native earthworms were recently introduced there and are now being spread by human activities. While past work has shown that plant communities in earthworm‐invaded areas change towards a lower diversity mainly dominated by grasses, the underlying mechanisms related to changes in the biotic interactions of the plants are not well understood. Here, we used a trait‐based approach to study the effect of earthworms on interspecific plant competition and aboveground herbivory. We conducted a microcosm experiment in a growth chamber with a full‐factorial design using three plant species native to northern North American deciduous forests, Poa palustris (grass), Symphyotrichum laeve (herb) and Vicia americana (legume), either growing in monoculture or in a mixture of three. These plant community treatments were crossed with earthworm (presence or absence) and herbivore (presence or absence) treatments. Eight out of the fourteen above‐ and belowground plant functional traits studied were significantly affected by earthworms, either by a general effect or in interaction with plant species identity, plant diversity level and/or herbivore presence. Earthworms increased the aboveground productivity and the number of inflorescences of the grass P. palustris. Further, earthworms and herbivores together affected root tissue density of P. palustris and the specific leaf area of V. americana. In this study, earthworm presence gave a competitive advantage to the grass species P. palustris by inducing changes in plant functional traits. Our results suggest that invasive earthworms can alter competitive and multitrophic interactions of plants, shedding light on some of the mechanisms behind invasive earthworm‐induced plant community changes in northern North America forests.

Effects of different soil and water conservation measures on plant diversity and productivity in Loess Plateau

Many soil and water conservation measures (SWCM) have been implemented in the Loess Plateau of China, and they have an impact on ecosystems all levels and involve complicated mechanisms. Previously, studies typically focused on a single factor's effect on diversity or productivity. With this background, the current investigation embarked on an extensive study, with vegetation survey conducted in the no measure plots (NM), vegetation measure plots (VM) and engineering measure plots (EM) in the Loess Plateau of China. We used structural equation models (SEM) to explain the mechanism by which SWCM affects plant productivity and diversity. VM have direct effects on plant diversity, and EM have direct effects on soil properties and community structure. The two measures also had indirect effects on plant functional traits and community structure. The results show that the changes in plant functional traits and community structure by SWCM decreased plant diversity, whereas the increase of productivity was primarily dominated by improvements in community structure, and we conclude that variability in plant diversity and productivity across different measures on the Loess Plateau was primarily due to the responses of different plants to variable soil properties and the community responses. It was also emphasized that vegetation measures were beneficial to the increase of biomass per plant, while engineering measures were more beneficial to the growth of dominant species. These findings provide a theoretical foundation for vegetation management and restoration after the application of different SWCM.

Experimental warming altered plant functional traits and their coordination in a permafrost ecosystem.

Knowledge about changes in plant functional traits is valuable for the mechanistic understanding of warming effects on ecosystem functions. However, observations have tended to focus on aboveground plant traits, and there is little information about changes in belowground plant traits or the coordination of above- and belowground traits under climate warming, particularly in permafrost ecosystems. Based on a 7-yr field warming experiment, we measured 26 above- and belowground plant traits of four dominant species, and explored community functional composition and trait networks in response to experimental warming in a permafrost ecosystem on the Tibetan Plateau. Experimental warming shifted community-level functional traits toward more acquisitive values, with earlier green-up, greater plant height, larger leaves, higher photosynthetic resource-use efficiency, thinner roots, and greater specific root length and root nutrient concentrations. However, warming had a negligible effect in terms of functional diversity. In addition, warming shifted hub traits which have the highest centrality in the network from specific root area to leaf area. These results demonstrate that above- and belowground traits exhibit consistent adaptive strategies, with more acquisitive traits in warmer environments. Such changes could provide an adaptive advantage for plants in response to environmental change.

Functional structure mediates the responses of productivity to addition of three nitrogen compounds in a meadow steppe.

Atmospheric nitrogen (N) deposition is altering grassland productivity and community structure worldwide. Deposited N comes in different forms, which can have different consequences for productivity due to differences in their fertilization and acidification effects. We hypothesize that these effects may be mediated by changes in plant functional traits. We investigated the responses of aboveground primary productivity and community functional composition to addition of three nitrogen compounds (NH4NO3, [NH4]2SO4, and CO[NH2]2) at the rates of 0, 5, 10, 20gNm-2yr-1. We used structural equation modeling (SEM) to evaluate how functional structure influences the responses of productivity to the three N compounds. Nitrogen addition increased community-level leaf chlorophyll content but decreased leaf dry matter content and phosphorus concentration. These changes were mainly due to intra-specific variation. Functional dispersion of traits was reduced by N addition through changes in species composition. SEM revealed that fertilization effects were more important than soil acidification for the responses of productivity to CO(NH2)2 addition, which enhanced productivity by decreasing functional trait dispersion. In contrast, the effects of (NH4)2SO4 and NH4NO3 were primarily due to soil acidification, influencing productivity via community-weighted means of functional traits. Our results suggest that N forms with different fertilizing and acidifying effects influence productivity via different functional traits pathways. Our study also emphasizes the need for in situ experiments with the relevant N compounds to accurately understand and predict the ecological effects of atmospheric N deposition on ecosystems.

Study on the relationship between functional characteristics and environmental factors in karst plant communities.

Environmental factors drive changes in plant functional traits, which in turn promote community recovery. The environmental conditions of the community are different at different recovery stages. Changing environmental factors may drive the changes in plant functional traits at the community level and affect species adaptation. We studied plant communities in five different recovery stages (herb, grass and shrub, shrub, tree and shrub, and tree) in the karst plateau of Zhenning, Guizhou (The vegetation in the study area has undergone a gradual natural recovery process after the forests were deforested in 1958–1960). We studied functional traits and their links to environmental factors. The main results include the following. (1) Over time, plant height, leaf dry matter content, leaf nitrogen content and leaf phosphorus content increased significantly in the tree stage, while leaf thickness and specific leaf area decreased significantly in the tree stage. (2) Soil organic carbon, soil N content, soil P content, soil C:P and soil C:K showed an increasing trend, and were significantly higher in tree stage than in other stages. Soil potassium content fluctuated and soil bulk density decreased gradually, reaching the lowest value in the tree stage, but the difference was not significant. (3) During the restoration process, the functional characteristics changed from a combination of plant communities with high specific leaf area and low dry matter content with a short plant height to plant communities with low specific leaf area and high dry matter content with a tall plant height. (4) As recovery proceeded, the study area gradually changed from a soil nutrient‐poor environment to a nutrient‐rich environment. Overall, the environmental factors vary greatly during the recovery of plant communities in karst areas. The plant community shifts from an aggressive (resource acquisition) to a conservative (environmental barrenness resistance) ecological strategy. The soil phosphorus content and soil C:K are the main environmental factors affecting the changes in functional traits during the restoration of karst plant communities in Zhenning.

Changes in plant functional traits and their relationships with environmental factors along an urban-rural gradient in Guangzhou, China

Abstract Rapid urbanization in southern China has had significant impacts on the monsoon evergreen broad-leaved forests and caused a series of environmental issues. How plants, in particular plant functional traits, respond to urbanization is hence of importance for their acclimation to changing environments. In this study, we investigated the changes of plant functional traits associated with plant competition and nutrient utilization strategies and their relationships with environmental factors along an urban-rural gradient in Guangzhou, China. Results showed that plant species in the urban forests had larger specific leaf area (SLA), higher leaf nitrogen (LN) content, and lower leaf carbon/nitrogen ratio (C:N) than those in the suburban and rural forests. Principal component analysis revealed that species in the urban, suburban, and rural forests were significantly separated by the first principal component, which was strongly related to SLA and leaf nutrient traits. Plant functional traits were also found closely related to soil pH, nitrogen, and copper content. Species with higher SLA and higher LN content were better adapted to the urbanization environment. Our findings indicate that the process of urbanization may change the composition of lower subtropical monsoon evergreen broad-leaved forests by favoring acquisitive-strategy species, and further influence ecosystem services.

Plant functional trait shifts explain concurrent changes in the structure and function of grassland soil microbial communities

Abstract Land‐use intensification drives changes in microbial communities and the soil functions they regulate, but the mechanisms underlying these changes are poorly understood as land use can affect soil communities both directly (e.g. via changes in soil fertility) and indirectly (e.g. via changes in plant inputs). The speed of microbial responses is also poorly understood. For instance, whether it is long‐term legacies or short‐term changes in land‐use intensity that drive changes in microbial communities. To address these topics, we measured multiple microbial functions, bacterial and fungal biomass and abiotic soil properties at two time intervals 3 years apart. This was performed in 150 grassland sites differing greatly in management intensity across three German regions. Observed changes in microbial soil properties were related to both long‐term means and short‐term changes in: abiotic soil properties, land‐use intensity, community abundance‐weighted means of plant functional traits and plant biomass properties in regression and structural equation models. Plant traits, particularly leaf phosphorus, and soil pH were the best predictors of change in soil microbial function, as well as fungal and bacterial biomass, while land‐use intensity showed weaker effects. Indirect legacy effects, in which microbial change was explained by the effects of long‐term land‐use intensity on plant traits, were important, thus indicating a time lag between plant community and microbial change. Whenever the effects of short‐term changes in land‐use intensity were present, they acted directly on soil microorganisms. Synthesis. The results provide new evidence that soil communities and their functioning respond to short‐term changes in land‐use intensity, but that both rapid and longer time‐scale responses to changes in plant functional traits are at least of equal importance. This suggests that management which shapes plant communities may be an effective means of managing soil communities and the functions and services they provide.

Functional diversity and composition of Caatinga woody flora are negatively impacted by chronic anthropogenic disturbance

Abstract Tropical plant assemblages can be taxonomically and phylogenetically impoverished by chronic anthropogenic disturbance (CAD), such as firewood collection and extensive grazing. However, to what extent the functional dimension responds to CAD is still unclear. Such knowledge is urgently required for predicting, preventing or even reversing the impacts of CAD. Chronic anthropogenic disturbance may operate as an ecological filter by selecting functional trait values (e.g. low wood density), thereby altering the functional composition and diversity of plant assemblages. We tested this hypothesis using 29 woody plant assemblages across three ontogenetic stages (seedlings, saplings and adults) in a 220‐km2 landscape of the Caatinga, northeast Brazil. We adopted a CAD index consisting of four indicators (proximity to urban centre and houses and the density of both people and livestock) and tested how well it explained the functional diversity and effect sizes (richness, evenness and dispersion) and composition (community‐weighted mean). Chronic anthropogenic disturbance affected several functional metrics across the three ontogenetic stages. However, CAD effects were stronger in adult communities by negatively affecting functional richness, dispersion and their effect sizes. CAD also altered the functional composition of leaf mass per area, woody density and leaf area of adult assemblages. Sapling communities were affected in terms of functional composition (leaf area, leaf dry matter and wood density), with positive and negative effects, while seedling assemblages responded positively to CAD only in terms of functional evenness and its effect size. Some changes in functional metrics were influenced by dominant Euphorbiaceae species across ontogenetic stages, especially in terms of leaf area and woody density. Synthesis. Chronic anthropogenic disturbance is an important driver of plant‐community functional organization across ontogenetic stages in the Caatinga. Adult assemblages are particularly sensitive and tend to lose functional niche space and support more acquisitive rather than conservative strategies as chronic anthropogenic disturbance increases. The proliferation of Euphorbiaceae disturbance‐adapted species can explain part of the community responses to chronic anthropogenic disturbance. Our findings highlight the ecological effects of chronic anthropogenic disturbance and show that it is a key influence on tropical biotas. Changes in plant functional traits associated with plant resource use are likely to affect ecosystem functioning and services provided by Caatinga.

Strong restrictions on the trait range of co-occurring species in the newly created riparian zone of the Three Gorges Reservoir Area, China

Abstract Aims Community assembly links plant traits to particular environmental conditions. Numerous studies have adopted a trait-based approach to understand both community assembly processes and changes in plant functional traits along environmental gradients. In most cases these are long-established, natural or semi-natural environments. However, increasingly human activity has created, and continues to create, a range of new environmental conditions, and understanding community assembly in these ‘novel environments’ will be increasingly important. Methods Built in 2006, the Three Gorges Dam, largest hydraulic project in China, created a new riparian area of 384 km2, with massively altered hydrology. This large, newly created ecosystem is an ideal platform for understanding community assembly in a novel environment. We sampled environment variables and plant communities within 103 plots located in both the reservoir riparian zone (RRZ) and adjacent non-flooded and semi-natural upland (Upland) at the Three Gorges Reservoir Area. We measured six traits from 168 plant species in order to calculate community-level distribution of trait values. We expected that the altered hydrology in RRZ would have a profound effect on the community assembly process for the local plants. Important Findings Consistent with previous work on community assembly, the distribution of trait values (range, variance, kurtosis and the standard deviation of the distribution neighbor distances) within all plots was significantly lower than those from random distributions, indicating that both habitat filtering and limiting similarity simultaneously shaped the distributions of traits and the assembly of plant communities. Considering the newly created RRZ relative to nearby sites, community assembly was different in two main ways. First, there was a large shift in the mean trait values. Compared to Upland communities, plant communities in the RRZ had higher mean specific leaf area (SLA), higher nitrogen per unit leaf mass (Nmass), and lower maximum height (MH). Second, in the RRZ compared to the Upland, for the percentage of individual plots whose characteristic of trait values was lower than null distributions, the reductions in the community-level range for SLA, Nmass, nitrogen per unit leaf area (Narea) and phosphorus per unit leaf area (Parea) were much larger, suggesting that the habitat filter in this newly created riparian zone was much stronger compared to longer established semi-natural upland vegetation. This stronger filter, and the restriction to a subset of plants with very similar trait values, has implications for predicting riparian ecosystems’ responses to the hydrological alterations and further understanding for human’s effect on plant diversity and plant floras.

Ecological succession in a changing world

Abstract Ecological succession – how biological communities re‐assemble and change over time following natural or anthropogenic disturbance – has been studied since the birth of ecology, and the resulting theoretical framework underpins many aspects of the discipline. Recently, the mechanistic basis of classic succession theory has been advanced by studies of plant and microbial interactions, functional traits, and retrogressive stages of ecosystem development. This special issue brings together a series of papers that highlight these contemporary novel approaches and how our understanding of ecological succession has advanced. Four key themes emerge from the issue: (a) generalizations about succession, (b) the influence of dispersal and habitat size on successional trajectories, (c) changes in plant functional traits during succession, and (d) belowground community interactions during long term during ecosystem development. Synthesis. The articles in the special issue highlight novel perspectives on succession theory, revealing the importance of historical contingency, disturbance severity, dispersal limitation, functional traits, and belowground community processes in determining patterns of ecosystem development. Together, they reinforce the importance of ecological succession in understanding the response of plant and microbial communities to disturbance in a changing world.

海岛植物不同演替阶段植物功能性状与环境因子的变化规律

PDF HTML阅读 XML下载 导出引用 引用提醒 海岛植物不同演替阶段植物功能性状与环境因子的变化规律 DOI: 10.5846/stxb201807051468 作者: 作者单位: 福建农林大学,福建农林大学,福建农林大学,云南大学,福建农林大学 作者简介: 通讯作者: 中图分类号: 基金项目: 福建省自然科学基金面上项目（2018J01699）；国家自然科学基金项目（31800401）；福建省教育厅科技项目（JAT170198） Summary of changes in plant functional traits and environmental factors in different successional stages of island plants Author: Affiliation: Fujian Agriculture and Forestry University,Fujian Agriculture and Forestry University,Fujian Agriculture and Forestry University,,Fujian Agriculture and Forestry University Fund Project: 省、部研究计划基金, 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物功能性状与环境之间的关系是功能性状研究的重点，环境因子驱使植物功能性状发生变化，进而推动群落发生演替。以平潭岛4个不同演替阶段的森林植被（灌草丛、针叶林、针阔混交林、常绿阔叶林）为研究对象，结合不同群落演替阶段的物种特征和群落结构，分析海岛不同演替阶段茎、叶功能性状的变化规律，以及功能性状与环境因子的关系。结果表明：（1）随着演替的进行，土壤养分和水分逐渐增加，土壤pH逐渐下降。比叶面积（SLA）、叶片氮含量（LNC）、叶片磷含量（LPC）、茎氮含量（SNC）、茎磷含量（SPC）下降后上升，叶厚度（LT）、叶片碳含量（LCC）、茎碳含量（SCC）与之相反，叶干物质含量（LDMC）、茎组织密度（STD）逐渐上升。（2）冗余分析表明，演替早期植物主要分布在土壤pH、容重高的贫瘠环境，拥有较高SLA、SNC、SPC、LPC的性状组合；演替后期植物主要分布在土壤养分和水分高的肥沃环境，拥有较高的STD、LDMC、LCC、LNC的性状组合。其中，土壤有机质和全氮含量是影响海岛植物演替过程中功能性状变化的关键环境因子。研究海岛植物功能性状与环境之间的关系随演替的变化规律，探讨各演替阶段功能性状和环境特征，以及功能性状如何响应环境变化。旨在为今后选择合适的树种进行海岛植被修复和重建提供依据。 Abstract:The relationship between plant functional traits and environment is the focus of functional traits research. Environmental factors drive the changes in plant functional traits, which in turn promote community succession. Based on the forest vegetation of four different succession stages (shrub-grassland, coniferous forest, mixed wood, and broadleaf forest) in Pingtan Island, this study combined the species characteristics and community structure of different community successional stages. We analyzed the changes in stem and leaf functional traits in different succession stages of island plants. Moreover, we explored the relationship between plant functional traits and environmental factors. The results showed the following. (1) With progress in succession, soil nutrient and water content gradually increased and the soil pH gradually decreased. The specific leaf area (SLA), leaf nitrogen content (LNC), leaf phosphorus content (LPC), stem nitrogen content (SNC), and stem phosphorus content (SPC) decreased initially, and then increased, Meanwhile, the leaf thickness (LT), leaf carbon content (LCC), and stem carbon content (SCC) increased initially, and then decreased. The leaf dry matter content (LDMC) and stem tissue density (STD) gradually increased. (2) The redundancy analysis showed that the early succession plants were mainly distributed in barren environments with high soil pH and high bulk density, and they presented higher SLA, SNC, SPC, and LPC. Plants in the late succession stages were mainly distributed in fertile environments with high soil nutrient and water content, and they presented higher STD, LDMC, LCC, and LNC. Therefore, soil organic matter and total nitrogen are the important environmental factors that affect the functional traits of island plants succession. We studied the relationship between plant functional traits and environment along with the changes in succession, understood the functional traits and environmental characteristics of each succession stage, and revealed how plant functional traits adapted to the environmental changes. The study provides the basis for the selection of suitable tree species for island vegetation restoration and reconstruction in the future. 参考文献 相似文献 引证文献

Short-term changes in plant functional traits and understory functional diversity after logging of different intensities: a temperate fir-beech forest experiment

The concept of plant functional traits has been demonstrated to be very effective in unravelling the ecological mechanisms governing plant community response to disturbance, especially when research is focused on short-term post-disturbance vegetation dynamics. In this study, we established an experiment to quantify how logging intensity affects the trait composition and functional diversity of understory communities in fir-beech forests in the Dinaric Mountains in Slovenia. Three different silvicultural treatments were implemented: control (no logging), 50% of the growing stock removed and 100% of the growing stock removed. Vegetation surveys of vascular plants were made before (in 2012) and two years after (in 2014) logging. Changes in species traits, C-S-R plant strategies (sensu Grime) and community-level functional diversity were analysed. The importance of traits such as small and light diaspores, short life span and anemochory increased with logging intensity. Moreover, species with the ability of both sexual and vegetative reproduction, longer flowering duration and overwintering green leaves increased in abundance after logging. C-S-R strategies mainly shifted from stress-tolerators in pre-logging conditions towards a more ruderal component in post-logging stands. Logging in the short term increased functional diversity, mainly due to newly colonized species being functionally dissimilar from persistent residents. Results suggest that logging intensity strongly influences the magnitude of change in both functional composition and diversity, which also has important implications for biodiversity conservation. At the landscape scale, increasing spatial heterogeneity by creating a mosaic of forest stands subjected to different logging intensities will likely contribute to the enhancement of plant functional diversity.

Interaction between PGPR and PGR for water conservation and plant growth attributes under drought condition

Drought is one of the key restraints to agricultural productivity worldwide and is expected to increase further. Drought stress accompanied by reduction in precipitation pose major challenges to future food safety. Strategies should be develop to enhance drought tolerance in crops like chickpea and wheat, in order to enhance their growth and yield. Drought tolerance strategies are costly and time consuming however, recent studies specify that plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGRs) can help plants to withstand under harsh environmental condition and enable plants to cope with drought stress. PGPR can act as biofertilizer and bioenhancer for different legumes and non-legumes. The use of PGPR and symbiotic microorganisms, may be valuable in developing strategies to assist water conservation in plants. The use of PGPR has been confirmed to be an ecologically sound way of enhancing crop yields by facilitating plant growth through direct or indirect mechanism. The mechanisms of PGPR for water conservation include secretion of exopolysaccharides, biofilm formation, alternation in phytohormone content, improvement in sugar concentration, enhancing availability of micro- and macronutrients and changes in plant functional traits. Similarly, plant growth regulators (PGRs) are specially noticed in actively growing tissues under stress conditions and have been associated in the control of cell division, embryogenesis, root formation, fruit development and ripening, and reactions to biotic and abiotic stresses and upholding water conservation status in plants. Previous studies also suggest that plant metabolites interact with plant physiology under stress condition and impart drought tolerance. Metabolites like, sugars, amino acids, organic acid and polyols play a key role in drought tolerance of crop plants grown under stress condition. It is concluded from the present study that PGRs in combination with PGPR consortium can be an effective formulation to promote plant growth and maintenance of plant turgidity under drought stress. This review is a compilation of the effect of drought stress on crop plants and described interactions between PGPR/PGRs and plant development, knowledge of water conservation and stress release strategies of PGPR and PGRs and the role of plant metabolites in drought tolerance of crop plants. This review also bridges the gaps that summarizes the mechanism of action of PGPR for drought tolerance of crop plants and sustainability of agriculture and applicability of these beneficial rhizobacteria in different agro-ecosystems under drought stress.

Previsual symptoms of Xylella fastidiosa infection revealed in spectral plant-trait alterations

Plant pathogens cause significant losses to agricultural yields and increasingly threaten food security1, ecosystem integrity and societies in general2-5. Xylella fastidiosa is one of the most dangerous plant bacteria worldwide, causing several diseases with profound impacts on agriculture and the environment6. Primarily occurring in the Americas, its recent discovery in Asia and Europe demonstrates that X. fastidiosa's geographic range has broadened considerably, positioning it as a reemerging global threat that has caused socioeconomic and cultural damage7,8. X. fastidiosa can infect more than 350 plant species worldwide9, and early detection is critical for its eradication8. In this article, we show that changes in plant functional traits retrieved from airborne imaging spectroscopy and thermography can reveal X. fastidiosa infection in olive trees before symptoms are visible. We obtained accuracies of disease detection, confirmed by quantitative polymerase chain reaction, exceeding 80% when high-resolution fluorescence quantified by three-dimensional simulations and thermal stress indicators were coupled with photosynthetic traits sensitive to rapid pigment dynamics and degradation. Moreover, we found that the visually asymptomatic trees originally scored as affected by spectral plant-trait alterations, developed X. fastidiosa symptoms at almost double the rate of the asymptomatic trees classified as not affected by remote sensing. We demonstrate that spectral plant-trait alterations caused by X. fastidiosa infection are detectable previsually at the landscape scale, a critical requirement to help eradicate some of the most devastating plant diseases worldwide.

Linking plant functional trait plasticity and the large increase in forest water use efficiency

AbstractElevated atmospheric CO2 concentrations are expected to enhance photosynthesis and reduce stomatal conductance, thus increasing plant water use efficiency. A recent study based on eddy covariance flux observations from Northern Hemisphere forests showed a large increase in inherent water use efficiency (IWUE). Here we used an updated version of the same data set and robust uncertainty quantification to revisit these contemporary IWUE trends. We tested the hypothesis that the observed IWUE increase could be attributed to interannual trends in plant functional traits, potentially triggered by environmental change. We found that IWUE increased by ~1.3% yr−1, which is less than previously reported but still larger than theoretical expectations. Numerical simulations with the Tethys‐Chloris ecosystem model using temporally static plant functional traits cannot explain this increase. Simulations with plant functional trait plasticity, i.e., temporal changes in model parameters such as specific leaf area and maximum Rubisco capacity, match the observed trends in IWUE. Our results show that trends in plant functional traits, equal to 1.0% yr−1, can explain the observed IWUE trends. Thus, at decadal or longer time scales, trait plasticity could potentially influence forest water, carbon, and energy fluxes with profound implications for both the monitoring of temporal changes in plant functional traits and their representation in Earth system models.

Erratum to: Changes in plant functional traits and water use in Atlantic rainforest: evidence of conservative water use in spatio-temporal scales

Erratum to: Changes in plant functional traits and water use in Atlantic rainforest: evidence of conservative water use in spatio-temporal scales

Cambios en la diversidad funcional del sotobosque y la tasa de descomposición frente a diferentes intensidades de uso silvopastoril en el noroeste de la Patagonia, Argentina

Functional diversity loss by human land-use changes is of great importance for achieving sustainable management, as it plays a key role in ecosystem functioning through a direct influence over ecological processes. In northwest Patagonian forests, livestock production is among the main activities affecting natural ecosystems. The aim of the study was to characterize changes in functional diversity of understory vegetation in sites with different silvopastoral use intensity, and the effects that these variations may have on rate of litter decomposition in mixed forests of cypress and coihue of southwest Rio Negro Province, Argentina. Changes in plant functional traits (life cycle, life style, architecture, habitat, leaf size, leaf texture and root system) were characterized, and the decomposition rate of each site's litter was quantified. Our results showed that both functional diversity index (FD Q ) and decomposition rate were higher under high silvopastoral use intensity, but the relationship was not significant. Results also showed that certain plant functional traits (i.e., rosette architecture, prostrate habitat and fern life form) have a significant effect on litter lost weight. Under high silvopastoral use intensity, the relative proportion of species with rosette architecture and prostrate habitat increases, which led to an increase in decomposition rate. This indicates that silvopastoral activity may modify the original community composition towards species with a rapid resource acquisition, altering also nutrient cycling. In this sense, ecosystem functioning seems to be influenced by certain functional traits, rather than functional diversity itself.

Effects of changing precipitation and warming on functional traits of zonal Stipa plants from Inner Mongolian grassland

The mechanisms driving changes in dominant plant species are the key for understanding how grassland ecosystems respond to climate change. In this study, we examined plant functional traits (morphological characteristics: plant height, leaf area, and leaf number; biomasses: aboveground, belowground, and total; and growth indices: root-to-shoot ratio, specific leaf area, and leaf mass ratio) of four zonal Stipa species (S. baicalensis, S. bungeana, S. grandis, and S. breviflora) from Inner Mongolian grassland in response to warming (control, +1.5, +2.0, +4.0, and +6.0?), changing precipitation (-30%, -15%, control, +15%, and +30%), and their combined effects via climate control chambers. The results showed that warming and changing precipitation had significant interactive effects, different from the accumulation of single-factor effects, on functional traits of Stipa species. The correlation and sensitivity of different plant functional traits to temperature and precipitation differed. Among the four species, the accumulation and variability of functional traits had greater partial correlation with precipitation than temperature, except for leaf number, leaf area, and specific leaf area, in S. breviflora, S. bungeana, and S. grandis. For S. baicalensis, the accumulation and variability of plant height, aboveground biomass, and root-to-shoot ratio only had significant partial correlation with precipitation. However, the variability of morphological characteristics, biomasses, and some growth indices, was more sensitive to temperature than precipitation in S. bungeana, S. grandis, and S. breviflora—except for aboveground biomass and plant height. These results reveal that precipitation is the key factor determining the growth and changes in plant functional traits in Stipa species, and that temperature mainly influences the quantitative fluctuations of the changes in functional traits.