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Rocky desertification is a prevalent environmental challenge across karst landscapes that hinders regional sustainable development. Understanding how soil properties and plant traits respond to increasing levels of rocky desertification is crucial for developing effective restoration strategies. Here, we investigated soil characteristics and intraspecific leaf stoichiometric traits of Pseudotsuga sinensis across a gradient of rocky desertification in a karst ecosystem. We employed principal component analysis to assess changes in soil properties and leaf chemical traits and used leaf trait network analysis to explore shifts in trait network topology. Our results revealed that severe desertification sites had soil with high bulk density and pH, and low levels of available nitrogen, phosphorus, magnesium, as well as soil organic carbon. Leaf stoichiometry shifted markedly along the gradient, with elevated nitrogen limitation and cation imbalance in degraded sites. Trait network analysis showed that network diameter and modularity increased while connectance decreased with rocky desertification, indicating reduced integration among traits. On the other hand, higher adaptation capacity to environmental harshness under moderate level of rocky desertification was also observed. These findings suggest that both soil properties and leaf traits would experience substantial shifts across rocky desertification gradient, with increasing functional fragmentation and nutrient limitation as degradation intensifies. Based on our results, we propose management strategies targeted to different levels of rocky desertification to mitigate its negative impacts and promote ecosystem recovery.

Spatial patterns and environmental gradients in plant traits can elucidate the relationships between plant characteristics, environmental factors, and ecosystem functions and can be used to develop the next generation of vegetation models for predicting vegetation distribution and functions. Studies of Plant traits across spatial scales have advanced significantly worldwide, including on the Tibetan Plateau (TP), the highest and largest plateau globally. Previous research on plant traits on the TP has been limited to specific areas, leaving the overall trend across the plateau unclear. In this study, we examined seven leaf traits—leaf thickness (LT), leaf dry matter content (LDMC), leaf area (LA), specific leaf area (SLA), and leaf carbon (LCC), nitrogen (LNC), and phosphorus (LPC) contents—in 1314 individuals at 237 sites within the alpine vegetation region above 3000 m on the TP to determine their distribution patterns across three spatial dimensions and their relationships with environmental factors. Our results indicated that, compared with Chinese plants, TP plants exhibited significantly greater LT, LDMC, and LNC but lower LA, LCC, and LPC. Except for SLA and LCC, most leaf traits showed significant spatial variability. Climate and soil explained 29.23 % of the total variations in traits. Radiation had the most pronounced effect on LDMC, LA, LNC, and LPC, whereas soil pH primarily constrained LT and LCC. Precipitation influenced most traits both directly and indirectly, with substantial overall effects. Temperature and soil nutrient had minimal influence on the regulation of leaf traits across most of the TP. Our findings suggest that alpine plants typically employ a conservative strategy to cope with the harsh conditions on the TP, but this strategy varies at broader spatial scales and longer environmental gradients, particularly in extreme environments such as the highest alpine regions.

Nowadays, atmospheric concentrations of nitrogen oxides (NOX) have increased rapidly and exceeded the threshold of ecosystems, inevitably affecting the plant growth and community stability, especially in urban green space. The increase of atmospheric NOX is also accompanied by natural and anthropogenic environmental change, which also bring severe environmental stresses on green vegetation. To better understand drivers that contribute to the vegetation changes, this study explored the interaction among atmospheric NOX, climate, terrain, and urbanization, and its impact on the tree leaf and forest community traits, using a dataset with 118 plots of tree communities composed of 5781 trees across distinct types of urban green space in Tianjin, a highly urbanized metropolis in China. The results indicated that atmospheric NOX concentration showed a positive association with urbanization and temperature, which co-limited the tree growth and resulted in the vegetation browning of urban green space. The responses of coniferous and broadleaved forests were different, whose understory herbaceous diversity and height had contrary tendencies to environmental change. Meanwhile, urbanization intensified atmospheric N deposition and heat island effect, increasing the leaf chlorophyll contents of tree species in urban green spaces. While leaf herbivory showed positive correlation with urbanization, temperature, and evaporation only in the high NOX regime. Overall, this study found that atmospheric NOX could be used as a good indicator of urbanization. These findings also advanced our recognition of the environmental driving factors of green vegetation dynamics, and provided references for the research of elsewhere.

Mediterranean forests represent critical areas that are increasingly affected by the frequency of droughts and fires, anthropic activities and land use changes. Optical remote sensing data give access to several essential biodiversity variables, such as species traits (related to vegetation biophysical and biochemical composition), which can help to better understand the structure and functioning of these forests. However, their reliability highly depends on the scale of observation and the spectral configuration of the sensor. Thus, the objective of the SENTHYMED/MEDOAK experiment is to provide datasets from leaf to canopy scale in synchronization with remote sensing acquisitions obtained from multi-platform sensors having different spectral characteristics and spatial resolutions. Seven monthly data collections were performed between April and October 2021 (with a complementary one in June 2023) over two forests in the north of Montpellier, France, comprised of two oak endemic species with different phenological dynamics (evergreen: Quercus ilex and deciduous: Quercus pubescens) and a variability of canopy cover fractions (from dense to open canopy). These collections were coincident with satellite multispectral Sentinel-2 data and one with airborne hyperspectral AVIRIS-Next Generation data. In addition, satellite hyperspectral PRISMA and DESIS were also available for some dates. All these airborne and satellite data are provided from free online download websites. Eight datasets are presented in this paper from thirteen studied forest plots: (1) overstory and understory inventory, (2) 687 canopy plant area index from Li-COR plant canopy analyzers, (3) 1475 in situ spectral reflectances (oak canopy, trunk, grass, limestone, etc.) from ASD spectroradiometers, (4) 92 soil moistures and temperatures from IMKO and Campbell probes, (5) 747 leaf-clip optical data from SPAD and DUALEX sensors, (6) 2594 in-lab leaf directional-hemispherical reflectances and transmittances from ASD spectroradiometer coupled with an integrating sphere, (7) 747 in-lab measured leaf water and dry matter content, and additional leaf traits by inversion of the PROSPECT model and (8) UAV-borne LiDAR 3-D point clouds. These datasets can be useful for multi-scale and multi-temporal calibration/validation of high level satellite vegetation products such as species traits, for current and future imaging spectroscopic missions, and by fusing or comparing both multispectral and hyperspectral data. Other targeted applications can be forest 3-D modelling, biodiversity assessment, fire risk prevention and globally vegetation monitoring.

The colorful “delayed leaf greening” is a common but overlooked phenomenon in phosphorus (P)-limited environments in habitats in tropical, subtropical and temperate forests, but the physiological mechanism underpinning it remains unclear. It is important to understand how allocation of phosphorus to major leaf P fractions shifts during leaf development, as a strategy for utilizing P efficiently. We measured concentrations of leaf nitrogen and P and five chemical P fractions, and eight leaf chemical element concentrations (K, Ca, Mg, Mn, Fe, Cu, Zn and Se) in young and mature leaves of six woody plants exhibiting delayed greening in China. We also measured leaf mass per area, photosynthetic rate, photosynthetic phosphorus-use efficiency, and soil nutrient concentrations. The results indicate six species exhibiting delayed greening had different leaf P concentrations during leaf development, but the same nitrogen concentrations. We further show major leaf chemical P fractions like metabolite P, nucleic acid P and lipid P showed differences in young and mature leaves. The concentration of lipid P, nucleic acid P, Pi and residual P significantly decreased from young to mature leaves, while that of metabolite P was constant. There was a greater allocation of P to phospholipids and metabolite P in mature leaves. The concentration of Cu and K were significantly higher in young leaves. This study provides new insight to investigate the roles of different P fractions in young and mature leaves, and how the allocation shifts for plants to utilize phosphorus.

The expansion of bamboo into neighboring plant communities is a common phenomenon in nature reserves. However, the role of climate factors and plant functional traits in the distribution of woody species after bamboo expansion remains unclear. Six functional traits of leaves of 180 individuals of 52 species, soil properties and air temperature were measured along an elevational gradient with different bamboo densities on Mt. Fanjingshan, Tongren City, Guizhou. Then, the direct and indirect effects of climate, soil properties, leaf traits and bamboo density on woody species distribution were detected. Our results showed that leaf traits were represented by two independent dimensions. The first dimension (PC1) is represented by the trade-off between the pairs leaf P, leaf N and leaf dry matter content, leaf C, representing nutrient use efficiency (NUE). The second dimension (PC2) was positively associated with leaf area, specific leaf area and leaf N, representing the leaf economics spectrum (LES). Climate, soil, leaf traits and bamboo density significantly explained 18% and 21% of the variance in species importance values for all species and evergreen species, respectively, but not for deciduous species. Air temperature had a positive indirect impact on the species importance value of all species via a negative direct impact on PC2, and air temperature affected the evergreen species importance value in two indirect ways: the first was to affect the species importance value positively and indirectly via PC2; the second was to affect the species importance value positively and indirectly through PC2 and PC1. However, bamboo expansion alone had no significant direct or indirect effects on species distribution. These results suggest that leaf traits are good predictors of woody species distribution after bamboo expansion in a mountain forest, and the effects of bamboo expansion are dependent on tree growth type, air temperature and leaf traits.

Tropospheric ozone (O3) increased globally in the 20th century, contributes to climate change and can have adverse effects on terrestrial ecosystems. The response of forest vegetation to ozone is modulated by species- and site-specific factors and visible foliar symptoms (VFS) are the only direct evidence of ozone effects on vegetation. VFS have been observed and reproduced under (semi-) controlled conditions and their field assessment has been largely harmonized in Europe. We analyzed ozone concentration and VFS data as measured at (respectively) 118 and 91 intensive monitoring sites of the International Co-Operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) spanning over five European biogeographic regions from 2005 to 2018. Average values for VFS were calculated accounting for the number of species present and their observed frequency. Spatial and temporal variation of ozone concentrations, VFS, and their relationships across Europe were then investigated by applying Generalized Linear Mixed Models (GLMMs) and combined GLMMs. Ozone concentrations exceeded 40 ppb on 37.3 % of the sites and were significantly higher (p

Low community stability and sustainability, accompanied by high maintenance cost was an important ecological problem in planted herbaceous communities in many cities. Investigation showed that the overwhelmingly majority of garden designers ignored the subtle interactions between plants and plants in community itself, as well as the fitness of plants to certain environment. Fortunately, CSR strategy methodology based on leaf traits could be a useful tool for reflecting plant functional groups, thus we can have a deeper understanding of the characteristics of various herbaceous plants. In this study, we used 318 common herbaceous plants in Shaanxi as experimental material to investigate leaf area (LA), leaf fresh weight (LFW) and leaf dry weight (LFW) of them. Their CSR strategies were determined using the 'StrateFy' analysis tool and were presented in a triangular distribution. The results showed that S-selection was responsible for the vast majority of herbaceous plants in garden design, C- selection took second place, and R- selection was the least. Sub-strategy (CS, S/CS, CR, CS/CSR, S/CSR and so on) also played a vital role in garden plants, which together accounted for 90.88% from all plant strategies. In terms of the representative families, the strategies of Labiatae and Asteraceae distributed widely, and the trade-off appeared in C-S axes of Gramineae and Liliaceae. Among three leaf traits, LA was of great importance to C- strategy, LDMC to S- strategy, and SLA was important to R-strategy. CSR strategy composition indicates the power of artificial selection, and reasonable collocation of different CSR strategies can create a better community. Thus, we propose that future investigations on CSR strategies in different regions all over the world should provide a reliable database for garden herbaceous species selection.

Resprouting of non-native tree invaders is a threat to tropical montane cloud forests and particularly to periurban forests. Resprouting is a common response of trees to disturbance in many ecosystems; however, little is known about the resprouting of woody exotic species with shade-tolerant characteristics that can slowly invade those forests. Furthermore, resprouting of woody invaders is a complex challenge for the control of invasive species since it is a major driver of reinvasion and persistence. In this study, we focus on the resprouting ability of a potential invader, Eriobotrya japonica, in a periurban cloud forest reserve of Xalapa, Mexico. We experimentally cut trees and juveniles in the secondary forest and clipped seedlings at the forest edge, and assessed resprout number, dimensions, emergence position, survival, and leaves per resprout. We then determined foliar traits of the newly produced leaves (leaf area (LA), specific leaf area (SLA), leaf mass area (LMA), leaf dry mass content (LDMC), and thickness). Our results show that resprouting occurred within a month in both tree stumps and clipped seedlings. Resprout survival was 50-80% in stumps, and 63-88% in clipped seedlings. Resprouts were produced mostly in the upper 5 cm below the cut. Leaf number was positively related to dimensions of the longest resprout. Some leaf traits of E. japonica were similar to those of shade-tolerant trees, but there is a combination of strategies since the species presents higher LA and thicker leaves than other native tree species, yet its LMA and LDMC are within the range presented by shade-tolerant species. Eriobotrya japonica is a woody invasive that partly behaves as a shade-tolerant tree and resprouts profusely and rapidly from stumps and clipped seedlings. Its resprouting ability is therefore a key trait by which to explain the invasive potential of this woody species.

Climbing plants that cover building walls (indirect green façades) are a nature-based solution for urban greening in dense urban areas. Green facades can provide important ecosystem service benefits such as cooling, biodiversity habitat and visualamenity and screening. However, as new buildings are constructed the urban form changes and this can create heavy shade that impacts the growth, health and function of existing green façade climbing plants. Climbing plants may respond to increased shade through plasticity in some leaf traits (e.g. specific leaf area, photosynthetic rate or leaf chlorophyll content). However, deciduous climbing plant species are likely to be more plastic than evergreen species as they have less conservative resource strategies.In this study we measured morphological, physiological and biochemical leaf traits of seven mature climbing plant species growing in full-sun and in response to the addition of heavy shade (via shade cloth). All seven climbing plant species significantly increased specific leaf area; whilst physiological traits relating to light compensation and thermal tolerance remained unchanged in response to heavy shade. Other physiological, biochemical or morphological traits only changed in response to heavy shade for certain species. There was a very similar level of phenotypic plastic response to shade by both deciduous and evergreen climbing plant species, except for photosynthetic capacity which was significantly more plastic (greater reduction) in deciduous species.Our results suggest most climbing plant species can maintain growth and physiological function when light conditions change from full-sun to heavy shade. These green façade plants are likely to maintain building wall coverage, healthy function and delivery of ecosystem service benefits in cities. In areas experiencing densification and new building shadows, deciduous climbing plant species appear to respond slightly better to heavy shade and may be more suitable for green façades that may become shaded by future building.

Mangroves are key components of productive ecosystems that provide a multitude of ecosystem goods and services. How these species will respond to future climates with more frequent and severe extreme temperatures has not received much attention. To understand how vulnerable mangroves are to future warming, we quantified photosynthetic heat tolerance and estimated thermal safety margins for thirteen mangrove species from the southwestern Indian coast. We quantified heat tolerance as temperatures that resulted in a 5 % (T 5 ) and 50 % (T 50 ) decline in photosystem II function, and thermal safety margins (TSM) as the difference between T 50 and maximum leaf temperatures. T 50 ranged from 48.9 °C in Avicennia Marina to 55.3 °C in Bruguiera gymnorhiza, with a mean of 53.3 °C for the thirteen species. Heat tolerance was higher for species with bigger leaves which experience higher leaf temperatures, but was not related to the other leaf traits examined. Heat tolerance was exceptionally high in these mangroves compared to other woody species. With their high tolerance and large safety margins these mangroves may be relatively less vulnerable to future climates with higher temperatures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Leaf chlorophyll content (LCC) is an important indicator of plant health. Earth observation facilitates LCC monitoring on large spatial scales and within short time intervals by retrieving canopy LCC from spectral signals. However, in-situ measurements are still necessary to validate the predicted values and the accurate quantification of LCC is labour-intensive and costly. Handheld leaf chlorophyll metres, such as the SPAD-502 (Konica Minolta) promise quick and non-destructive in-situ LCC estimates. SPAD values can be easily converted to LCC by established calibration curves that are based on measurements of single plant species. Due to these practical advantages, the application of SPAD-LCC calibration curves, originally derived in an agricultural context (Markwell et al., 1995), has become common practice in field studies. Although associated with a variety of uncertainties, the transfer of general SPAD-to-LCC calibration equations to natural ecosystems has not yet been comprehensively investigated. In this study, we test the reliability of SPAD-to-LCC conversions in three structurally different semi-natural grassland areas with mixed species compositions. We measured SPAD values in the field and determined the corresponding LCC of the very leaf samples via chemical extraction and spectrophotometry. Our results show that SPAD-to-LCC conversion equations lack accuracy in semi-natural grassland with mixed species compositions (n = 157, R2 = 0.046, p

The single functional differentiation of lianas and trees has been explored at both local and regional scales. Traits are not independent of each other, and the differentiation and integration of the multiple traits of lianas and trees under contrasting environments remain unclear. We used trait correlation networks to distinguish the topological relationships of multiple traits of lianas and trees in dry versus wet forests. We evaluated 17 plant traits of 16 liana and 16 tree species. Compared with trees, the trait networks of lianas were more modularized in both wet and dry forests, indicating that these fluctuating environments were less influential on lianas compared to trees. In the wet forest, economic traits showed higher connectedness in lianas whereas hydraulic traits were more connected in trees. Thus, it was cost-effective for plants to increase the connectivity of specific key traits when resource conditions were poor. The number and composition of trait modules varied with life form and environmental conditions, with alternative designs being common for plants to cope with their local environments. This study revealed plant adaptations can be improved through greater variation in trait correlations, providing new insights on why lianas are more abundant and diverse in highly seasonal forests.

Outdoor air pollution in urban areas, especially particulate matter (PM), is harmful to human health. Urban trees and shrubs provide crucial ecosystem services such as air pollution mitigation by acting as natural filters. However, urban greenery comprises a particular biodiversity, and different plant species vary in their capacity to accumulate PM. Twenty-two plant species were analyzed and selected according to their leaf traits, the different fractions of PM accumulated on the leaves (large - PM L , coarse - PM C , and fine - PM F ) and their chemical composition. The study was conducted in four city zones: urban traffic (UT), urban background (UB), industrial (IND), and rural (RUR), comparing winter (W) and summer (S) seasons. The average PM levels in the air and accumulated on the leaves were higher in W than in S season. During both seasons, the highest PM accumulated on the leaves was recorded at the UT zone. Nine species were selected as the most suitable for accumulating PM L , seven as the most efficient for accumulating PM C, and six for accumulating PM F . The leaf area and leaf roundness were correlated negatively with PM accumulation. The evergreen species L. nobilis was indicated as suitable for dealing with air pollution based on PM 10 and PM 2.5 values recorded in the air. Regarding the PM element and metal composition, L. nobilis, Photinia x fraseri, Olea europaea, Quercus ilex and Nerium oleander were selected as species with notable elements and metal accumulation. In summary, the study identified species with higher PM accumulation capacity and assessed the seasonal PM accumulation patterns in different city zones, providing insights into the species interactions with PM and their potential for monitoring and coping with air pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Exploring the adaptation strategies of plants in alpine regions could provide reliable suggestions for plant conservation. As an irreplaceable organ, leaf functional traits and correlation have the closest contact with environment, which is the main index to measure survival fitness of plants. Rhododendron, the typical broad-leaved shrubs, are an important constituent of alpine ecosystems, especially in the Tibetan Plateau and the surrounding regions. The scaling relationship of leaf mass (LM) and leaf area (LA) of natural shrubs is still lacking. In this study, we measured LA, leaf fresh mass (LFM), leaf dry mass (LDM), leaf dry matter content (LDMC), leaf water content (LWC), and specific leaf area (SLA) of six Rhododendron spp. (Rhododendron maculiferum, Rhododendron capitatum, Rhododendron oreodoxa, Rhododendron przewalskii, Rhododendron watsonii, Rhododendron rufum) to study the leaf traits and scaling relationship between LM and LA. Our results showed that: the leaf traits varied significantly in species. R. rufum belongs to slow investment-return, R. przewalskii and R. capitatum belong to quick investment-return. The scaling relationship showed that, the scaling exponent (α) for R. maculiferum and R. capitatum were significantly greater than 1.0, while the α for R. oreodoxa was less than 1.0, which meant that the increase of leaf dry mass did not keep pace with the increase of leaf fresh mass in some species. The scaling exponent of LFM vs. LA were all greater than unity at six species. The LDM vs. LA scaling relationship was similar to LFM vs. LA to a large extent. Only R. oreodoxa showed a scaling exponent that was equal to one. For all species, the coefficients of determination (i.e. R2) for LFM vs. LA were always greater than that of LDM vs. LA. Thus, it might be more meaningful to describe the relationship between LM and LA using LFM vs. LA. Our results suggest that the six species locate in different ends on the leaf economic spectrum. With the increase of leaf dry mass, the fresh mass does not keep pace. Six alpine Rhododendron species incomplete support diminishing returns law. In future studies, the influence of various environmental pressures on the scaling relationship between leaf mass and leaf area relationships should not be neglected when analyzing the relationships of foliar biomass allometry allocation patterns. Our study highlighted that the diminishing returns for alpine plants, which provided a new perspective to understand the adaptation of alpine evergreen plants to harsh habitats.

Plant functional traits play a key role in the assessment of ecosystem processes and properties. Optical remote sensing is ascribed a high potential in capturing those traits and their spatiotemporal patterns. In vegetation remote sensing, reflectance-based retrieval methods are either statistical (relying on empirical observations) or physically-based (based on inversions of a radiative transfer model, RTM). Both trait retrieval approaches remain poorly investigated regarding phenology. However, within the phenology of a plant, its leaf constituents, canopy structure, and the presence of phenology-related organs (i.e., flowers or inflorescence) vary considerably – and so does its reflectance. We, therefore, addressed the question of how plant phenology affects the predictive performance of both statistical and RTM-based methods and how this effect differs between traits. For a complete growing season, we weekly measured traits of 45 herbaceous plant species together with hyperspectral canopy reflectance (ASD FieldSpec III). Plants were grown in an experimental setup. The investigated traits comprised Leaf Area Index (LAI) and the leaf traits chlorophyll, anthocyanins, carotenoids, equivalent water thickness, and leaf mass per area. We compared the predictive performances of PLSR models and three variants of PROSAIL inversions based on (1) all observations and based on (2) a phenological subset where flowering plants were excluded and only those observations most suitable for modeling were kept. Our results show that both statistical and RTM-based trait retrievals were largely affected by phenology. For carotenoids for example, R2 decreased from 0.58 at non-flowering canopies to 0.25 at 100% flowering canopies. Temporal trends were diverse. LAI and equivalent water thickness were best estimated earlier in the growing season; chlorophyll and carotenoids towards senescence. PLSR models showed generally higher bias than the PROSAIL-based retrieval approaches. Lookup-table inversion of PROSAIL in combination with a continuous wavelet transformation of reflectance showed highest accuracies. We found RTM-based retrieval not to be as accurate and transferable as previously indicated. Our results suggest that phenology is essential for accurate retrieval of plant functional traits and varies depending on the studied species and functional traits, respectively.

The dataset presented in this article describe 33 species or varieties of service crops cultivated in population under non-limiting conditions. The description was made at flowering. 41 variables were measured on leaves, stems, roots and seeds. They related to plant phenology (1), morphology (13), physiology (1), biochemistry (18), size (6) and reproduction (2). This dataset is made available to enable comparisons between datasets, extended analysis and meta-analysis on cover crops. The data presented in this article were partly used in the research article entitled “A trait-based characterization of cover plants to assess their potential to provide a set of ecological services in banana cropping systems” (Damour et al., 2014).

The data presented in this article describe 21 species that can be found in banana cropping systems: 17 cover crops species, 2 spontaneous species and 2 cultivars of banana. The cover crop species belongs mainly to Fabaceae family, but also to Poaceae, Euphorbiacea and Asteraceae. Four repetition of each species were cultivated individually, in the field, under non-limiting conditions. 40 variables were measured on whole plant, leaves and roots, at flowering or after six months of growth for longer cycle species. This dataset is made available to provide data on these species, enable comparisons between datasets and meta-analysis on cover crop or on species presented in arable fields. The data presented in this article were used in the research articles entitled “Trait-based characterisation of cover plants' light competition strategies for weed control in banana cropping systems in the French West Indies” (Tardy et al. 2015) and “Trait-based characterization of soil exploitation strategies of banana, weeds and cover plant species” (Tardy et al. 2017).

Abstracts: The spatial differentiation of plant functional traits reflects the survival strategies of plants to adapt to climate change. However, the mechanisms that guide this phenomenon, especially along latitude gradients, remain unclear. Leaf traits data, namely specific leaf area, leaf nitrogen content, leaf phosphorus content and leaf dry matter content in northeast China along the latitude was used to identify potential underlying climate and soil drivers of latitudinal gradients in plant traits. (1) Leaf traits of all life forms showed a wide variation across the study locations in northeastern China and the variation was strongly correlated with latitude. The latitudinal interpretation of leaf N and P content spatial differentiation is higher than other functional traits. (2)The latitudinal differences of functional traits were significantly correlated with climatic factors. With the increase of annual average temperature and annual average precipitation (MAT and MAP), specific leaf area (SLA) of leaves increased significantly, while leaf dry matter content (LDMC) decreased significantly (P

Rainfall plays a crucial role in the removal of particulate matter (PM) from plant leaves, influencing PM retention and the environmental behaviour of harmful substances that accumulate in PM. This study examined the PM retention capacity, particle size distributions, and wash-off rates of leaf surface PM from three common green tree species in northern China during two natural rainfall events (light rain: 8.3 mm; heavy rain: 54.2 mm), to investigate the relationship between the leaf traits, PM retention capacity, and PM wash-off process. Our results found that leaf morphometric characteristics, such as leaf size, length, width, and aspect ratio (length-to-width), had a negative and significant correlations with the PM retention capacity, but had no significant correlation with the leaf surface PM wash-off rate. Smaller leaves with low aspect ratios exhibited greater stability under external disturbances than large leaves with high aspect ratios, resulting in a higher PM retention capacity and lower wash-off rate. Ridges and grooves enhanced the PM retention capacity by increasing the leaf roughness. Rainfall could wash off all particle size ranges of leaf surface PM without altering their mechanical composition. Larger particles were more easily washed off. Euonymus japonicus, with its small leaf size and low aspect ratio, exhibited the highest PM retention capacity. Its curled leaf shape also hindered light rain from washing off leaf surface PM. Forsythia suspensa, with denser grooves and ridges compared with Prunus serrulata, exhibited a rougher leaf surface and higher PM retention capacity. However, this roughness may reduce wettability, making it easier for runoff to form on the leaf surface and dislodge leaf surface PM, resulting in F. suspensa having the highest wash-off rate. Our results highlight the synergy of different leaf traits on PM retention capacity and the PM stability after rainfall., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Global change influences plant growth by affecting plant morphology and physiology. However, the effects of global change factors vary based on the climate gradient. Here, we established a global database of leaf traits from 192 experiments on elevated CO 2 concentrations (eCO 2 ), drought, N deposition, and warming. The results showed that the leaf mass per area (LMA) significantly increased under eCO 2 and drought conditions but decreased with N deposition, whereas eCO 2 levels and drought conditions reduced stomatal conductance and increased and decreased photosynthetic rates, respectively. Leaf dark respiration (Rd) increased in response to global change, excluding N deposition. Leaf N concentrations declined with eCO 2 but increased with N deposition. Leaf area increased with eCO 2 , N deposition, and warming but decreased with drought. Leaf thickness increased with eCO 2 but decreased with warming. eCO 2 and N deposition enhanced plant water-use efficiency (WUE), eCO 2 and warming increased photosynthetic N-use efficiency (PNUE), while N fertilization reduced PNUE significantly. eCO 2 produced a positive relationship between WUE and PNUE, which were limited under drought but increased in areas with high humidity and high temperature. Trade-offs were observed between WUE and PNUE under drought, N deposition, and warming. These findings suggest that the effects of global change factors on plants can be altered by complex environmental changes; moreover, diverse plant water and nutrient strategy responses can be interpreted against the background of their functional traits., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Predicting the impact of grazing on desert steppes' vegetation is crucial for sustainable management. The competitor, stress-tolerator and ruderal (CSR) theory has offer valuable insights into plant adaptive capacity and predicting changes in vegetation structure. However, whether adaptive strategy of desert steppe change with grazing intensity is not understood yet. We conducted a comprehensive assessment of the effects of 19 years of varying grazing intensities (no grazing: CK; light grazing: LG; moderate grazing: MG; heavy grazing: HG) on plant CSR strategies. Within the desert steppe ecosystem, the prevailing plant community strategy leaned towards SR (Stress-tolerant/Ruderal) under non-grazed conditions (C:S:R = 2:48:50 %). However, as grazing intensity increased, the S-score increased significantly from 48 % to 62 % while the R-score decreased from 50 % to 36 %. This trend persisted across functional groups and species, except for shrubs, due to the convergent response of traits and ecological strategies of these species under intense grazing pressure. Furthermore, our findings reveal that the shift of CSR on the community level was primarily influenced by soil nutrients and soil density, but not by evolutionary history (phylogenetic conservatism of traits). This suggests that plant traits co-evolved under prolonged environmental stress, resulting consistent variation and ecological strategies in desert grasslands. Overall, long-term grazing reinforced selective pressure, creating a simplified plant community structure with low levels of diversity and productivity, dominated by conservative resource-use strategy. This study highlights the mechanisms of plant adaptation to the prolonged grazing disturbance in desert steppes., (Copyright © 2023. Published by Elsevier B.V.)

Heavy grazing generally reduces grassland biomass, further decreasing its carbon sink. Grassland carbon sink is determined by both plant biomass and carbon sink per unit biomass (specific carbon sink). This specific carbon sink could reflect grassland adaptative response, because plants generally tend to adaptively enhance the functioning of their remaining biomass after grazing (i.e. higher leaf nitrogen content). Though we know well about the regulation of grassland biomass on carbon sink, little attention is paid to the role of specific carbon sink. Thus, we conducted a 14-year grazing experiment in a desert grassland. Ecosystem carbon fluxes, including net ecosystem CO 2 exchange (NEE), gross ecosystem productivity (GEP) and ecosystem respiration (ER), were measured frequently during five consecutive growing seasons with contrasting precipitation events. We found that heavy grazing reduced NEE more in drier (-94.0 %) than wetter (-33.9 %) years. However, grazing did not reduce community biomass much more in drier (-70.4 %) than wetter years (-66.0 %). These meant a positive response of specific NEE (NEE per unit biomass) to grazing in wetter years. This positive response of specific NEE was mainly caused by a higher biomass ratio of other species versus perennial grasses with greater leaf nitrogen content and specific leaf area in wetter years. In addition, we also detected a shift of grazing effects on specific NEE from positive in wetter years to negative in drier years. Overall, this study is among the first to reveal the adaptive response of grassland specific carbon sink to experimental grazing in plant trait view. The stimulation response of specific carbon sink can partially compensate for the loss of grassland carbon storage under grazing. These new findings highlight the role of grassland adaptive response in decelerating climate warming., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The role of plants in alleviating aerosol pollution has drawn extensive attention. Most studies focus on compositions of aerosol particles on urban plants, while the leaf traits related to particle retention have not yet been intensively studied. This study selected five typical urban plants (Loropetalum chinense, Rhododendron simsii, Euonymus japonicus, Photinia × fraseri, Osmanthus fragrans), and employed scanning electron microscope (SEM) and ion chromatography, aiming to investigate the accumulation features of aerosol particles and the relationships between leaf traits and particle retention. Results show that aerosol particles were mainly retained on the adaxial leaf surface, the fine particles (Φ ≤ 2.5 μm) were the predominant components (77.8 % by number) on the leaves, and the dominant water-soluble ions of particles were Ca 2+ , SO 4 2- . By comparison, E. japonicus and P. fraseri were efficient in the retention of fine and coarse particles (2.5 <Φ ≤ 10 μm), but L. chinense was capable to retain more large particles (Φ > 10 μm). The correlation analysis indicates that leaf traits are closely related to the accumulation of aerosol particles. The result shows that plant leaves with larger stomatal area, lower stomatal density, smaller specific leaf area and higher in epicuticular wax content can retain more aerosol particles. This result indicates that the leaves are capable of retaining aerosol particles via the synergy of multiple leaf traits, such as higher wax content and the fewer but larger stomata on their leaf surfaces. This study is helpful to understand the interactions between leaf traits and particle retention, and it further contributes to the selection of potential dust-retaining plants, which is of great significance for the alleviation of urban air pollution.3 - . By comparison, E. japonicus and P. fraseri were efficient in the retention of fine and coarse particles (2.5 <Φ ≤ 10 μm), but L. chinense was capable to retain more large particles (Φ > 10 μm). The correlation analysis indicates that leaf traits are closely related to the accumulation of aerosol particles. The result shows that plant leaves with larger stomatal area, lower stomatal density, smaller specific leaf area and higher in epicuticular wax content can retain more aerosol particles. This result indicates that the leaves are capable of retaining aerosol particles via the synergy of multiple leaf traits, such as higher wax content and the fewer but larger stomata on their leaf surfaces. This study is helpful to understand the interactions between leaf traits and particle retention, and it further contributes to the selection of potential dust-retaining plants, which is of great significance for the alleviation of urban air pollution., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The growing population in cities is causing a deterioration of air quality due to the emission of pollutants, causing serious health impacts. Trees and urban forests can contribute through the interception and removal of air pollutants such as particulate matter (PM). The dry deposition of PM by vegetation depends on air pollutant concentration, meteorological conditions, and specific leaf traits. Several studies explored the ability of different plant species to accumulate PM on leaf structures leading to the development of models to quantify the PM removal. The i-Tree Eco is the most used model to evaluate ecosystem services provided by urban trees. However, fine particulate matter (PM 2.5 ) removal is still calculated with a poorly evaluated function of deposition velocity (which depends on wind speed and leaf area) without differentiating between tree species. Therefore, we present an improvement of the standard model calculation introducing a leaf trait index to distinguish the species effect on PM net removal. We also compared model results with measurements of deposited leaf PM by vacuum filtration. The index includes the effect of morphological and functional leaf characteristics of tree species using four parameters: leaf water storage, deposition velocity, resuspension rate and leaf washing capacity. Leaves of 11 common urban tree species were sampled in representative areas of the city of Ferrara (Italy) and at different times of the year from 2018 to 2021. This includes four deciduous broadleaf trees (Tilia cordata, Platanus acerifolia, Acer platanoides, Celtis australis), three evergreen broadleaf trees (Quercus ilex, Magnolia grandiflora, Nerium oleander), and four conifers (Thuja orientalis, Cedrus libani, Pinus pinaster, Picea abies). The results provide significant advancement in assessing PM removal using decision support tools such as models to properly select tree species for future urban tree planting programs aimed at improving air quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Identifying ecological strategies based on functional traits can help us better understand plants' adaptations and changes in ecological processes, and thus predict the impact of climate change on ecosystems, especially in the vulnerable alpine grasslands. Herein, we investigated the plant CSR strategies of four grassland types (alpine meadows, AM; alpine meadow steppes, AMS; alpine steppes, AS; and alpine desert steppes, ADS) and its functional groups (grasses, sedges, legumes, and forbs) along the east-to-west gradient of decreasing precipitation on the northern Tibetan grasslands by using Grime's CSR (C: competitor, S: stress tolerator, and R: ruderal) analysis. Although alpine grasslands were dominated by S-strategy, our results also indicated that AM with higher water, nitrogen (N) and phosphorus (P) availability had significantly lower S-strategy values and relatively higher C- and R-strategy values (C: S: R = 6: 63: 31 %) than those in AMS (C: S: R = 3: 94: 3 %,), AS (C: S: R = 3: 87: 10 %), and ADS (C: S: R = 1: 94: 5 %). The CSR strategy values of forbs and legumes showed greater variability compared with grasses and sedges in the environmental gradient. Furthermore, water variability on the precipitation gradient eventually affected plant traits and CSR strategies through soil N and P availability and pH. Our findings highlighted that plant CSR strategies were regulated by the availability of soil resources, and plants adopted more flexible adaptation strategies in relatively resource-rich environments. This study sheds light on the mechanisms of plant adaptation to the changing environment in the alpine grasslands., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this study, Cucurbita pepo L., one of the most cultivated, consumed and economically important crop worldwide, was used as model plant to test the toxic effects of the four most abundant microplastics identified in contaminated soils, i.e. polypropylene (PP), polyethylene (PE), polyvinylchloride (PVC), and polyethyleneterephthalate (PET). Cucurbita plants were grown in pots with increasing concentrations of the microplastics, then plant biometry, photosynthetic parameters and ionome of treated vs. untreated samples were compared to evaluate the toxicity of each plastic. All the pollutants impaired root and, especially, shoot growth. Specific and concentration-dependant effects of the different microplastics were found, including reduction in leaf size, chlorophyll content and photosynthetic efficiency, as well as changes in the micro- and macro-elemental profile. Among all the microplastics, PVC was identified as the most toxic and PE as the less toxic material. PVC decreased the dimensions of the leaf lamina, the values of the photosynthetic performance index and the plant iron concentration to a higher extent in respect to the other treatments. Microplastic toxicity exerted on the growth of C. pepo raises concerns about possible yield and economic loss, as well as for risks of a possible transfer into the food chain., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The replacement of dominant sedges/grasses with secondary forbs is common in alpine rangelands, but the underlying plant ecological strategies and their relevance to leaf traits and their variabilities of different plant functional groups remain largely unknown. Here, we measured key leaf traits and analyzed the competitor, stress-tolerator and ruderal (CSR) strategies of major species with different functional groups (sedges, grasses and forbs) in an alpine meadow along a degradation gradient on the Tibetan Plateau. Our results indicated that S-selected species were dominant in both non-degraded (C:S:R = 1:95:4%) and severely degraded (C:S:R = 2:87:11%) meadows. However, there was a shift from S- to R-strategy in the communities after rangeland degradation. More specifically, sedges and grasses with a "conservative" strategy maintained stronger S-strategy to tolerate degraded and stressful conditions. In contrast, forbs with an "opportunistic" strategy (increase 9.5% in R-score) tended to adapt to degraded stages. Moreover, 51.1% and 23.9% of the increased R-scores in forbs were accounted by leaf mass per area and specific leaf area, respectively. Generally, higher leaf water and nitrogen contents coupled with larger variations in leaf traits and flexible SR strategies in forbs enabled them to capitalize on lower soil water and nutrient availability. Our findings highlighted that the contrasting strategies of plant species in response to the decrease in available resources might lead to niche expansion of secondary forbs and loss of diversity in the degraded alpine meadow. The emerging alternative stable states in the degraded rangelands might bring about a predicament for rangeland restoration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Biochar (BC) is a carbonaceous material obtained by pyrolysis of organic waste materials and has been proposed as a soil management strategy to mitigate global warming and to improve crop productivity. Once BC has been applied to the soil, its imperfect and incomplete mixing with soil during the first few years and the standard agronomic practices (i.e. tillage, sowing) may generate spatial heterogeneity of the BC content in the soil, which may have implications for soil properties and their effects on plant growth. We investigated how, after two agronomic seasons, the spatial heterogeneity of olive-tree prunings BC applied to a vertisol affected soil characteristics and wheat growth and yield. During the second agronomic season and just before wheat germination, we determined the BC content in the soil by an in-situ visual categorization based on the soil darkening, which was strongly correlated to the BC content of the soil and the soil brightness. We found a high spatial heterogeneity in the BC plots, which affected soil characteristics and wheat growth and yield. Patches with high BC content showed reduced soil compaction and increased soil moisture, pH, electrical conductivity, and nutrient availability (P, Ca, K, Mn, Fe, and Zn); consequently, wheat had greater tillering and higher relative growth rate and grain yield. However, if the spatial heterogeneity of the soil BC content had not been taken into account in the data analysis, most of the effects of BC on wheat growth would not have been detected. Our study reveals the importance of taking into account the spatial heterogeneity of the BC content., (Copyright © 2016. Published by Elsevier B.V.)

The importance of plants in the accumulation of organic contaminants from air and soil was recognized to the point that even regulatory predictive approaches now include a vegetation compartment or sub-compartment. However, it has recently been shown that many of such approaches lack ecological realism to properly evaluate the dynamic of air/plant/soil exchange, especially when environmental conditions are subject to sudden variations of meteorological or ecological parameters. This paper focuses on the development of a fully dynamic scenario in which the variability of concentrations of selected chemicals in air and plant leaves was studied weekly and related to the corresponding meteorological and ecological parameters, to the evaluate their influence. To develop scenarios for modelling purposes, two different sampling campaigns were performed to measure temporal variability of: 1) polycyclic aromatic hydrocarbon (PAH) concentrations in air of a clearing and a forest site, as well as in leaves of two broadleaf species and 2) two important leaf and canopy traits, specific leaf area (SLA) and leaf area index (LAI). The aim was to evaluate in detail how the variability of meteorological and ecological parameters (SLA and LAI) can influence the uptake/release of organic contaminants by plants and therefore air concentrations. A principal component analysis demonstrated how both meteorological and ecological parameters jointly influence PAH air concentrations. SLA, LAI, as well as leaf density were showed to change over time and among species and to be directly proportional to leaf/canopy uptake rate. While hazelnut had the higher leaf uptake rate, maple became the most important species when considering the canopy uptake rate due to its higher LAI. Other species specific traits, such as the seasonal variation in production of new leaves and the timing of bud burst, were also shown to influence the uptake rate of PAHs by vegetation., (Copyright © 2014 Elsevier B.V. All rights reserved.)