Abstract Aims With climate change, extreme drought events occur frequently around the world, and there is an urgent need to understand the resilience and influencing factors of trees after extreme drought. Methods Seven dominant tree species in karst evergreen and deciduous broad-leaved mixed forest in Guilin, Guangxi were selected to analyze the dynamic differences of xylem water transport function and its correlation with xylem characteristics and environmental factors at the end of extreme drought and after drought. Important findings (1) At the end of extreme drought, the percentage loss of xylem hydraulic conductivity (PLC) of all tree species except Cinnamomum camphora was higher than or close to 50%, and the highest was 87.92%.PLC of all species decreased linearly with the increase of xylem saturation water content at the end of extreme drought. PLC of porous species had significant positive and negative correlations with xylem density (WD) and xylem saturation water content (SWC), respectively, indicating that xylem water storage capacity was an important factor affecting water transport function of karst trees under extreme drought. (2) PLC of Fraxinus chinensis decreased significantly for the first time in the spring of the following year after extreme drought, and the formation of new vessels may be the strategy for restoring water transport function after extreme drought. The PLC of Choerospondias axillaris and Quercus acutissima, Quercus glauca, Boniodendron minius and Machilus calcicola decreased significantly for the first time on the 3rd and 13th day after extreme drought, respectively. The refilling of embolized vessels may be the strategy to restore water transport function of these species. (3) After the extreme drought event, the PLC recovery degree of all tree species at the last 6 sampling times was significantly positively correlated with the mean saturated water vapor pressure deficit (VPD) within 3 days before the current sampling time, indicating that the degree of air dryness had an important effect on the hydraulic function recovery of karst trees after extreme drought after the soil moisture condition recovered. (4) During the recovery process after extreme drought, many tree species showed embolism degree close to or even higher than that at the end of extreme drought, and the embolism fatigue degree of annular porous wood species was higher than that of loose porous wood species.

Aims As a crucial organ for plants to conduct matter and energy exchange with the external environment, the leaf's anatomical structure changes can directly reflect the adaptation strategies of plants to diverse habitats. This study aims to conduct research on the dominant plants in different habitats of Dajiuhu wetland, Mt. Shennongjia, and investigate the adaptive response of plant leaf anatomical structure traits to habitats with different water levels. Methods We selected six different habitats (xeric meadow (HA), moderate- xeric meadow (HB), hygrophyte- mesophyte meadow (Z), degraded semi-hygrophyte marshes (SA), hygrophyte herbaceous marshes (SB), hygrophyte peat bogs (SC)) in Dajiuhu wetland in Shennongjia as the study area. Six herbaceous plants, including Carex argyi, Rhynchospora chinensis, Scirpus karuisawensis, Eragrostis pilosa, Calamagrostis pseudophragmites, Agrostis matsumurae were collected from the Dajiuhu wetland and the leaf anatomy of these species were studied by using paraffin sectioning method. Important findings The results showed that: (1) the adaptation structures of different plants to the changes in habitat water level differed. Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis grew in swampy habitats with good water conditions. When the water level increased, the air cavity, vascular bundle and upper and lower epidermal cell cross-section significantly increased. The leaf thickness and xylem diameter in vascular bundles increased significantly in Carex argyi and Rhynchospora chinensis; (2) Eragrostis pilosa, Calamagrostis pseudophragmites and Agrostis matsumurae were distributed in drier dry and mesic meadows, and most structures in leaf transection did not show significant differences between habitats. Only the width and thickness of bulliform cells and upper epidermal cell thickness of Eragrostis pilosa, along with the lower epidermal cell thickness of Calamagrostis pseudophragmites, increased when the habitat water level decreased. Eragrostis pilosa and Agrostis matsumurae are C4 plants with trichomes or protuberances on the leaf surface, which may be related to the drought resistance. The developed aerenchyma and conducting tissues of Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis ensured the flow of gas and water. The study of the anatomical structure traits of plant leaves in different habitats reflects the strategies of the wetland plants to cope with the changes in ground water level. It can provide a reference for exploring the adaptation of plants to environmental water changes.

Drought stress represents a critical challenge to global agriculture, severely compromising plant growth and crop productivity through its disruption of intracellular signaling networks, with particular emphasis on protein kinase-mediated pathways and transcriptional regulation. In this study, we identified and characterized ZmDNL1 as a novel transcriptional regulator that serves as a negative modulator of drought tolerance in maize. Through comprehensive biochemical analyses, we demonstrated that ZmDNL1 physically interacts with ZmYAB15, a known negative regulator of drought tolerance, and potentiates its transcriptional regulatory activity. Most significantly, our investigation revealed that ZmSnRK2.10-mediated phosphorylation of three specific N-terminal residues in ZmDNL1 effectively attenuates ZmYAB15's transcriptional activity while maintaining the structural integrity of the ZmDNL1-ZmYAB15 protein complex, ultimately enhancing drought tolerance. These findings elucidate a previously unrecognized regulatory mechanism in which ZmSnRK2.10 orchestrates drought tolerance through phosphorylation-dependent fine tuning of the ZmDNL1–ZmYAB15 transcriptional regulatory module. Beyond advancing our fundamental understanding of drought response mechanisms in maize, this study provides valuable molecular targets for precision breeding strategies aimed at developing drought-resilient crop varieties.

Aims Populus euphratica and Tamarix ramosissima are two dominant species in the Daliyaboyi oasis, located at the tail of the Keriya River in the hinterland of the Taklamakan Desert. Against the backdrop of a warming and wetting climate trend in Northwest China, the relationship between the radial growth of these two species and climate change remains unclear. This study aimed to identify the limiting factors for the radial growth of P. euphraticaand T. ramosissima and to examine the characteristics of their growth-climate relationships in the conditions of a warming and wetting climate.

Methods Tree-ring samples of P. euphraticaand T. ramosissima were collected from two sites with different groundwater depths (1.0 m and 4.4 m) at the Daliyaboyi oasis. Standard chronologies were established for the two species, and the relationships between tree-ring width index and runoff and climatic factors for both species were analyzed. The differences in the climate responses of these two species were also explored.

Important findings The results indicated that P. euphratica and T. ramosissima with different groundwater depths have different responses to climate factors. With a groundwater depth of 1.0 m, the radial growth of P. euphratica was significantly and positively correlated with precipitation in April of the previous year and April of the current year. Meanwhile, the radial growth of T. ramosissima was significantly and positively correlated with runoff in June of the previous year and precipitation in February of the current year, and was significantly and negatively correlated with air temperature in December of the previous year. With a groundwater depth of 4.4 m, the radial growth of P. euphratica was significantly and positively correlated with air temperatures in January of the previous year and January of the current year, as well as with the Palmer Drought Severity Index (PDSI) from January of the previous year to June of the current year and from August to September of the current year. Meanwhile, the radial growth of T. ramosissima was significantly and positively correlated with runoff in June of the previous year, temperatures in September of the previous year, and precipitation in December of the previous year, as well as with temperatures in April of the current year. Sliding correlation analysis suggested that, under the influence of climate warming and wetting in the Taklamakan Desert, the positive response of P. euphratica radial growth to runoff factors (January to March) weakened at a groundwater depth of 1.0 m. In contrast, T. ramosissima showed an increased positive response to precipitation in April of the previous year and runoff from January to February of the previous year. With a groundwater depth of 4.4 m, the radial growth of P. euphratica showed a shift from a positive to a significant negative correlation with air temperature during April to May and July to August of the previous year, as well as during April to May and July to August of the current year, and the relationship between radial growth of P. euphratica to PDSI changed from significant positive correlation to non-significant correlation. The relationship between radial growth of T. ramosissima and precipitation and PDSI changed from negative correlation to positive correlation. In conclusion, P. euphratica demonstrates greater dependence on long-term climate factors at the deep groundwater depth, while T. ramosissima is more sensitive to short-term hydrological factors.

In higher plants, stomatal movements represent a critical physiological process that matains cellular water homestasis while enabling photosynthetic gas exchange. Open stomata 1 (OST1), a key protein kinase in the abscisic acid (ABA) signaling cascade, has been established as a central regulator of stomatal dynamics. This study reveals that two highly conserved mitogen-activated protein kinase 1 (MAP4K1) and MAP4K2 are positive regulators in ABA promoted stomatal closure, and ABA-activated OST1 potentiates MAP4K1/2 through phosphorylation at conserved serine and threonine residues (S166, T170, and S479/S488). The activated MAP4K1, in turn, phosphorylates two critical downstream targets: plasma membrane H⁺-ATPase 2 (AHA2) at residues T858, T881, and Y946, and slow anion channel-associated 1 (SLAC1) at T114 and S116. Functional analysis demonstrates that the phosphomimetic (3D: S166D/T170D/S479D) MAP4K1, but not non-phosphorylatable (3A: S166A/T170A/S479A) MAP4K1, could fully restore drought tolerance and reduced water loss in detached leaves of map4k1map4k2 double mutant. Our findings delineate a previously unrecognized signaling module comprising OST1–MAP4K1/2–AHA2/SLAC1, which crucially modulates ABA-mediated stomatal regulation. This work advances our mechanistic understanding of phosphorylation cascades governing plant water relations and stress responses.

Hydrogen sulfide (H₂S), a well-established gaseous signaling molecule, can effectively enhance plant tolerance to various environmental stresses. However, there is still a lack of suitable methods to release H₂S in agricultural production, and the mechanism by which H₂S improves stress resistance remains poorly understood. Here, we show the novel role of sodium butyrate (NaB) in producing H₂S consistently in rice rhizosphere soil and the epigenetic mechanism of H₂S to enhance rice drought tolerance. We found that NaB increased sulfate-reducing bacteria (SRB) abundance in the rhizosphere soil, resulting in higher expression of sulfite reductase (SiR), and consequently increased H₂S production. Mechanistic investigation showed that H₂S enhanced the level of H4K5ac in promoter regions of drought-tolerant genes, facilitating their expression by repressing the histone deacetylase (HDAC) gene OsHDA710. Loss-of-function mutants of OsHDA710 exhibited enhanced drought tolerance compared to wild-type (WT) plants, while OsHDA710 overexpression plants showed drought hypersensitivity. Moreover, we demonstrated that OsHDA710 could bind directly to promoters of drought-tolerance genes by recognizing the TGACC motif. Our findings illustrate an efficient way to produce H₂S and a novel mechanism for H₂S in improving the drought resistance of plants.

Background & Aims: Desiccation tolerance (DT) is a remarkable survival strategy in plants, allowing them to withstand extreme water deficits and resume full metabolic function upon rehydration. While this trait is crucial for life in arid environments, its underlying mechanisms vary significantly across the plant kingdom. As pioneers of terrestrial ecosystems, bryophytes exhibit exceptional DT, with the desert moss Syntrichia caninervis representing a model organism for its extraordinary resilience. Despite growing interest in its stress physiology, systematic syntheses addressing its integrated adaptive strategies across multiple biological levels remain limited. A comprehensive analysis of DT in S. caninervis is thus critical to unraveling its role in shaping plant evolution, optimizing survival in harsh climates, and providing novel genetic resources for crop improvement.

Progress: This review presents a systematic elucidation of the multi-level adaptive strategies for DT in S. caninervis. Morphologically, features such as inward leaf curling, surface papillae, and hyaline awns constitute a first line of defense. Physiologically, the moss employs an efficient osmotic adjustment system, a robust antioxidant defense network, and mechanisms for protecting subcellular structures, which collectively enable the rapid recovery of photosynthesis. Multi-omics analyses have revealed a two-phase survival strategy: entering a quiescent state via cellular protection and metabolic depression during dehydration, followed by the rapid activation of cellular repair and metabolic recovery upon rehydration. The molecular basis of this tolerance is linked to the significant expansion and tandem duplication of key gene families, such as late embryogenesis abundant proteins (LEA) and early light-inducible proteins (ELIP), alongside synergistic regulation by diverse transcription factors. Furthermore, the establishment of an efficient genetic transformation system has validated the function of over 60 stress-responsive genes with proven potential for enhancing drought and salt tolerance in crops.

Prospects: Current research on the DT mechanisms of S. caninervis is advancing rapidly, yet critical knowledge gaps persist in understanding its genetic architecture, signaling pathways, and evolutionary trajectories. Addressing these fundamental questions requires multidisciplinary approaches integrating genomics, proteomics, metabolomics, and developmental biology. This line of investigation holds significant implications for elucidating the evolutionary innovation of plant stress tolerance, identifying the drivers of adaptation to extreme environments, and deciphering the intricate regulatory networks governing cellular survival. Systematic exploration of S. caninervis will ultimately provide both a theoretical framework for plant adaptation and a valuable gene repository for breeding “climate-smart” drought-resistant crops.

Aims: Precipitation is one of the pivotal parameters for the desert ecosystems. Analyzing the diversity and stability of soil microbial communities across precipitation gradients would provide crucial insights into the environmental adaptability of the desert bacteria.

Methods: Seventy-five soil samples (0-10 cm depth) were collected from deserts at the southern margin of the Tarim Basin, spanning a mean annual precipitation (MAP) gradient from 26.26 to 91.43 mm, which corresponds to the MAP of Qiemo County (QM, 26.26 mm), Minfeng County (MF, 53.10 mm), Hetian County (HT, 59.77 mm), Pishan County (PS, 69.26 mm), and Bachu County (BC, 91.43 mm). Through high-throughput sequencing and co-occurrence network modeling, we compared soil bacterial community diversity and stability.

Results: The results indicated that: (1) different precipitation conditions significantly affected the composition, diversity and community structure of desert soil bacteria at the southern margin of the Tarim Basin. Pseudomonadota, Actinomycetota, Bacteroidota, Bacillota and Gemmatimonadota were the dominant phyla of bacterial communities. Despite the higher relative abundance of specific bacteria, the composition and diversity of the whole soil bacterial communities were more similar to those of common bacterial communities and significantly different from those of specific bacterial communities. (2) The desert soil bacteria at the southern margin of the Tarim Basin were mainly cooperative. The key bacteria belong to S0134_terrestrial_group, Motococcus and Bacillus, etc. The stability of co-occurrence network was influenced by precipitation. Sufficient precipitation can improve the stability of soil bacterial co-occurrence network, while precipitation frequency had a stronger correlation.

Conclusion: Bacterial composition and diversity in desert soils at the southern margin of the Tarim Basin are governed by soil moisture and saline-alkaline constraints, with cooperative interactions dominating microbial networks, while the precipitation frequency is significantly correlated with the stability of soil bacterial community. These results help to understand how desert ecosystems respond to their environment.

Background & Aim: This study aims to clarify the species diversity, distribution patterns, and environmental adaptation mechanisms of the genus Calligonum, in order to provide a scientific basis for its taxonomic revision. Global taxonomic data and multi-source databases including Global Biodiversity Information Facility (GBIF) were integrated to clarify its global distribution pattern; morphological measurements and comparative analyses of achenes from Central Asian specimens in the Tashkent Plant Herbarium (TASH) collection were conducted; a systematic investigation of its phylogenetic relationships, chromosomal variations, and ecological adaptation mechanisms was carried out through a multidisciplinary literature review.

Review Results: Calligonumwas widely distributed across arid regions from the Sahara to Central Asia, with Central Asia serving as its distribution and diversity center (34 recorded species). As the eastern margin of its distribution, China hosted 23 species, 17 of which were shared with Central Asia. This disjunct circum-Mediterranean distribution pattern may be associated with geological events such as the uplift of the Himalayas. The distribution of Calligonum was co-influenced by moisture, temperature, and soil factors. It was primarily found in arid zones with annual precipitation below 200 mm, exhibiting significant interspecific divergence in water-use strategies. Low temperatures and seasonal variations restricted its northward expansion, and it showed a preference for low-salinity, highly alkaline, and sandy soil types. The genus employed multi-level adaptive strategies, including physiological regulation and stoichiometric adjustments, to cope with arid conditions, thereby demonstrating clear ecological niche differentiation.

Perspectives: As a keystone taxon in the arid regions of Central Asia, Calligonum exhibits rich species diversity and rapid evolutionary potential. Future studies should integrate multidisciplinary approaches such as genomics and ecology to enhance understanding of its speciation and adaptation mechanisms. Furthermore, comprehensive conservation strategies focusing on germplasm preservation and ecological restoration should be promoted to ensure the long-term sustainability of the genus and its ecological functions.

Climate change creates novel environmental conditions that plant species must adapt to. Since plants are finely tuned to the seasonality of their environments, shifts in their phenology serve as some of the most compelling evidence of climate change’s impact. Understanding how key fitness-related phenological traits, such as flowering onset, respond to novel environments is crucial for assessing species’ plasticity and/or adaptive potential under climate change. Here, we investigated the onset of flowering in Fragaria vesca (woodland strawberry; Rosaceae) by translocating genotypes between four sites along a south–north gradient in Europe, encompassing its entire latitudinal distribution range with varying temperatures, precipitation patterns, and photoperiods. At each site, we included a reduced precipitation treatment using rainout shelters to simulate drought conditions and assess their impact on flowering onset. Our findings revealed that southern and central European genotypes exhibited a delayed onset of flowering when translocated to the northernmost site. In contrast, no difference among genotypes was found in the onset of flowering when grown in more southerly sites. Reduced precipitation accelerated flowering across several sites and all genotypes, irrespective of their latitudinal origin. Overall, northern European genotypes showed a greater capacity to adjust their onset of flowering in response to the different photoperiods and temperatures across the latitudinal gradient compared to southern European genotypes, suggesting that they may be more resilient to shifting environmental conditions. Differences in phenotypic plasticity among genotypes translocated to higher versus lower latitudes highlight the role of photoperiod in evaluating a species’ capacity to cope with climate change.

Understanding plant adaptive strategies that determine species distributions and ecological optima is crucial for predicting responses to global change drivers. While functional traits provide mechanistic insights into distribution patterns, the specific trait syndromes that best predict elevational optima, particularly in less-studied regions such as the Himalayas, remain unclear. This study employs a novel hierarchical framework integrating morphological, anatomical, and physiological traits to explain elevational distributions among 310 plant species across a 3,500-m gradient (2,650–6,150 m). We analyzed 95,000 floristic records collected from 4,062 localities spanning 80,000 km² in Ladakh, NW Himalayas, India, to define elevational optima and link them with 17 functional traits from over 7,800 individuals. We assessed the roles of moisture and cold limitations on trait–optima relationships by comparing two contrasting habitats (dry steppe and wetter, colder alpine). The predictive power of functional traits was more pronounced in the alpine species facing more extreme abiotic stress than the steppe species. Our results indicate that conservative life history strategies strongly predict elevational optima in alpine areas, while drought avoidance and competitive dominance are key in steppe habitats. Trait syndromes combining short stature, compact growth forms, enhanced storage tissues, and features promoting water-use efficiency (δ¹³C), freezing resistance (fructan levels), and nutrient retention (high root nitrogen and leaf phosphorus) explained 61% of the variation in alpine species' optima. Conversely, lifespan and clonal propagation determined the optima of steppe species at lower elevations. The study emphasizes the importance of functional trait combinations in determining elevational optima, highlighting that alpine species prioritize resource conservation and stress tolerance, while steppe species focus on competitive growth strategies. This multi-trait approach contrasts with previous research focusing on single trait–elevation relationships, providing novel insights into the diverse mechanisms shaping elevational distributions and offering valuable predictive power for assessing vegetation responses to future climate change.

In the context of climate change intensification and increasing limitation of arable land， improving drought tolerance in forest trees has emerged as a critical breeding goal. However， achieving enhanced stress resistance without compromising growth and biomass production remains a major challenge. In this study， transgenic 84K poplar （Populus alba×P. glandulosa ‘84K’） lines constitutively overexpressing PagPYL4 gene， an abscisic acid（ABA） receptor gene， were developed， and their physiological and growth responses were evaluated under drought stress. The results showed that under the influence of exogenous ABA， the overexpression of PagPYL4 gene significantly altered stomatal aperture in plants. Under short-term drought treatment， compared with the wild type， the overexpression of PagPYL4 gene reduced water loss and improved drought tolerance； however， it also inhibited stomatal conductance and photosynthetic rate， leading to a significant decrease in growth rate of plant height and ground diameter. Our findings demonstrated that while PagPYL4 overexpression effectively enhanced drought resistance， its indiscriminate activation can impose substantial growth penalties. This highlighted the importance of spatially and temporally regulated gene expression strategies to balance stress resilience and biomass productivity in future tree breeding programs.

Drought severely impedes plant growth and production as a primary abiotic stress. GIGANTEA (GI) regulates flowering and responds to various stresses in model plants; however, its function remains poorly understood in non-model plants. In this study, a Citrus limon GI homologous (CiGI) was identified and two alternative splicing transcripts (CiGIα and CiGIβ) were found. CiGIα overexpressing tobacco exhibited early flowering and drought sensitivity, whereas the phenotype of CiGIβ-overexpressing plants was similar to that of wild-type (WT) plants. Overexpression of CiGIα in citrus increased drought sensitivity and upregulated citrus FLOWERING LOCUS T (CiFT) expression, and downregulation of CiGI enhanced drought tolerance. Further studies revealed that CiGIα, CiGIβ, and LATE ELONGATED HYPOCOTYL (CiLHY) form a complex that binds to the Nuclear Factor YA1 (CiNF-YA1) promoter and activates its expression. Subsequently, CiNF-YA1 activates the expression of NADP-DEPENDENT MALIC ENZYME 2 (CiNADP-ME2) by binding its promoter, leading to increased reactive oxygen species (ROS) accumulation, which enhances plant drought sensitivity. Exogenous ROS treatment induced citrus flowering and reduced drought tolerance. Furthermore, the CiGI–CiLHY complex also activates CiFT and may participate in the regulation of citrus flowering. These results reveal a novel mechanism by which CiGI regulates citrus flowering and drought tolerance.

Warm temperate forests have the large potential to sequester atmospheric carbon dioxide (CO₂), while the interannual variability (IAV) of net forest ecosystem carbon exchange (NEE) in the global carbon cycle is still not fully understood. In this study, we conducted eddy-covariance measurement to investigate the IAV of carbon fluxes and concurrent influencing factors in a warm temperate natural oak forest from 2017 to 2022. Our results showed the natural oak forest was a strong CO₂ sink with an increase of 27.79 g C m⁻² a⁻¹ in annual carbon sequestration, resulting from a larger increase in annual gross primary production (GPP) than that of annual ecosystem respiration (Re). Precipitation in spring (PPT_spring) negatively influenced annual GPP, soil water content in spring (SWC_spring) negatively influenced annual Re, while the water conditions had lesser effect on annual NEE attributing to the synchronous changes of annual GPP and annual Re. Increase of temperature in autumn (Ta_autumn) delayed the end date of the growing season, leading to the increase in annual carbon sequestration. In addition, carbon fluxes did not significantly decrease under dramatic reduction of summer precipitation, indicating that warm temperate natural oak forest had a high resistance to seasonal drought. Our study helped us to better understand the mechanisms underlying forest carbon fluxes in response to drought in the context of future climate change.

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

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

Aims The accumulation of nutritional components in plants is critically linked to their survival capacity and productivity. Investigating how arbuscular mycorrhizal fungi (AMF) inoculation regulates drought tolerance in plants through nutrient component changes in various organ will establish a theoretical framework for applying AMF to improve crop resilience under water-limited conditions.
Methods The study employed a controlled pot experiment with two water regimes (75% vs. 55% field capacity) and AMF inoculation treatments, using oat (Avena sativa) cultivar ‘Bayou 1’. Mycorrhizal colonization rates were quantified at jointing and filling stages, followed by analysis of non-structural carbohydrates (NSC), carbon (C), nitrogen (N), phosphorus (P) contents in root, stem, and leaf. Grain yield was recorded at the maturity stage.
Important findings In oat plants inoculated with AMF under drought stress, the AMF colonization rate, plant height, and root-to-shoot ratio were significantly enhanced, resulting in 13.31% increase in grain yield. Notably, these improvements in growth parameters and yield exceeded those observed in AMF-inoculated plants under well-watered conditions. Furthermore, AMF inoculation under drought stress increased soluble sugar accumulation in stem and leaf. Concurrently, the contents of C, N, P in root, stem, leaf, as well as the leaf C:N significantly increased, especially the contents of P in leaf. In contrast, the leaf N:P significantly declined. Redundancy analysis revealed that the contents of leaf soluble sugars, and stem C, root N contents served as key indicators explaining variations in growth traits and grain yield under drought stress and AMF inoculation, respectively. Overall, AMF inoculation under drought conditions enhanced oat drought tolerance and hence improved grain yield, primarily attributed to increase AMF colonization rate, which facilitated synergistically the accumulation of soluble sugar and C, N, P in organs, and modulated the leaf stoichiometric ratios (C:N and N:P).

When and how disjunct distributions of biological taxa arose has long attracted interest in biogeography, yet the East Asian–Tethyan disjunction is understudied. Cupressus (Cupressaceae) shows this disjunction, with 10 species in East Asia and three in the Mediterranean region. Here we used target-capture sequencing and obtained 1991 single-copy nuclear genes, plus complete plastomes, to infer the evolutionary history of Cupressus. Our phylogenomic reconstruction resolved four well supported clades in Cupressus, but revealed significant phylogenetic conflicts, with inter-lineage gene flow, incomplete lineage sorting and gene tree estimation error all making important contributions. The Chengiana clade most likely originated by hybridization between the ancestors of the Himalayan–Hengduan Mountains and subtropical Asia clades, whereas orogenic and climatic changes may have facilitated gene flow within the Himalayan–Hengduan Mountains clade. Molecular dating suggested that the most recent common ancestor of Cupressus appeared in East Asia around the middle Eocene period and then became continuously distributed across Eurasia. The East Asian–Tethyan disjunction arose when the Mediterranean and Himalayan–Hengduan Mountains clades diverged, likely to have been driven by Eocene/Oligocene declines in global temperature, then reinforced by the ecogeographic barrier created by the uplift of the Qinghai–Tibet Plateau. Niche shifts in the common ancestor of the Mediterranean clade, and signatures of selection in genes for drought and salt tolerance, probably indicate adaptation of this clade to local conditions. Overall, our study suggested that in-depth phylogenomic analyses are powerful tools in deciphering the complex evolutionary history of the origin of East Asian–Tethyan disjunction of organisms, especially gymnosperms.

The physiological response mechanisms of trees to climate change are complex, particularly across varying elevations and among different tree species. In this study, we collected tree ring samples from two dominant conifer species (Picea crassifolia and Pinus tabuliformis) at three elevations at the edge of the Tengger Desert. We used tree-ring width (TRW) and tree ring oxygen isotopes (δ¹⁸O_TR) to investigate how species and elevations affect their responses to climate change. Pearson’s correlation analysis and relative importance analysis were used to study the specific response processes of the two conifers to climate. The results showed that the TRW was mainly controlled by Standardized Precipitation Evapotranspiration Index (SPEI) during the growing season, which means that drought stress had the greatest effect on it. And δ¹⁸O_TR mainly responded to summer relative humidity. Both TRW and δ¹⁸O_TR of P. crassifolia showed higher sensitivity to climate change. This sensitivity is largely attributed to the rapid uptake of precipitation by its developed shallow-rooted root system, which allows it to retain the precipitation signal in both TRW and δ¹⁸O_TR. However, P. crassifolia may be more susceptible to drought stress and growth decline or even death in the context of a warming region. Our results are important for understanding the impacts of climate change on forest ecosystems using multiple indicators and developing corresponding ecological conservation measures.

The calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) Ca²⁺ sensors play crucial roles in the plant's response to drought stress. However, there have been few reports on the synergistic regulation of drought stress by CBL-CIPK and abscisic acid (ABA) core signaling components. In this study, we discovered that ZmCIPK33 positively regulates drought resistance in maize. ZmCIPK33 physically interacts with and is enhanced by phosphorylation from ZmSnRK2.10. Drought stress can activate ZmCIPK33, which is partially dependent on ZmSnRK2.10. ZmCIPK33 in combination with ZmSnRK2.10 can activate the slow anion channel ZmSLAC1 in Xenopus laevis oocytes independently of CBLs, whereas ZmCIPK33 or ZmSnRK2.10 alone is unable to do so. Furthermore, ZmCIPK33 phosphorylates ZmPP2C11 at Ser60, which leads to a reduction in the interaction between ZmPP2C11 and ZmEAR1 (the ortholog of Arabidopsis Enhancer of ABA co-Receptor 1) and weakens the phosphatase activity of ZmPP2C11, consequently, enhancing the activity of ZmSnRK2.10 in an in vitro assay and in the in-gel assay of the zmcipk33 mutant. Our findings provide novel insights into the molecular mechanisms underlying the reciprocal enhancement of Ca²⁺ and ABA signaling under drought stress in maize.

The north-south transitional zone in central China is a climatic and ecological sensitive area, and the southern margin of Pinus tabuliformis distribution, yet regional response to climate has not been investigated. Here, we developed different regional chronologies from 14 samplings along an east-west gradient in the Funiu Mountains. Correlation results indicated that regional tree growth was mainly limited by temperature and precipitation in May, especially for YM. Temperature in the south and precipitation in the north were significant limiting effects, except in LCM, where trees were more limited by temperature in the south than precipitation in the north. The limiting effect of temperature in May gradually weakened from east to west, while the effect of precipitation in May was higher in YM (east) and BB (west) than in LCM (middle), and the promoting effect of precipitation in the north was stronger than that in the south. The self-calibrating Palmer Drought Severity Index (scPDSI) had significant positive correlations with tree growth from April to June, with the highest correlation in May. Tree growth increased in the 1970s–80s and then decreased after the 1990s indicated that the growth had degraded under global warming. This result supports the ecological marginal effect theory of growth degeneration of P. tabuliformis in NSTZ under global warming. However, whole regional tree growth also showed stronger recovery and resilience under extreme drought, the resilience basically restored to the pre-disturbance level after three years, which is obviously contradictory with tree growth trend and needs to be further studied.

During the restoration of degraded ecosystems, different shrub species often segregate along environmental water gradients. However, the physiological mechanisms driving this segregation remain unclear. To address this gap, we conducted a drought stress experiment (70%–80% field water holding capacity, CK; 40%–50% field water holding capacity, MD; 20%–30% field water holding capacity, SD) to explore the physiological mechanisms driving the dominance of different shrub species at various stages of ecosystem restoration. Salix gordejevii, a species dominant in the early stages of restoration with high water availability, and Caragana microphylla, a species dominant in the later stages under low water availability, were studied. The results showed that the living state index (LSI) of S. gordejevii was significantly lower than that of C. microphylla under drought stress (P < 0.05). Differences in plant hydraulics and water-use strategies explained how these species adapt to varying soil moisture conditions. Salix gordejevii employed a proactive water-use strategy with lower water-use efficiency (WUE) and reduced resistance to xylem embolism (xylem water potentials corresponding to 50% loss of conductivity, P₅₀), making it better suited to environments with more abundant water. In contrast, C. microphylla adopted a conservative water-use strategy. This strategy was characterized by increased WUE and enhanced resistance to drought-induced xylem embolism, which allowed it to thrive under more drought-prone conditions. Importantly, hydraulic efficiency (⁠K_leaf, K_s, and K₁) emerged as the primary determinant of living state in both S. gordejevii (47.30%) and C. microphylla (62.20%). The lower embolism resistance of S. gordejevii (⁠P₅₀ = 1.3 MPa) made it more susceptible to xylem cavitation, leading to a decline in hydraulic efficiency under SD. In contrast, C. microphylla’s higher embolism resistance (⁠P₅₀ = 2.3 MPa) enabled it to maintain stable hydraulic conductance across all drought treatments. These differences in hydraulic efficiency, driven by xylem embolism resistance, were key factors influencing shifts in shrub dominance during ecosystem restoration. These findings provide a physiological explanation for the replacement of shrub species during ecosystem restoration, where soil moisture is the main limiting factor.

Maize (Zea mays L.) growth and yield are severely limited by drought stress worldwide. Stomata play crucial roles in transpiration and gas exchange and are thus essential for improving plant water-use efficiency (WUE) to help plants deal with the threat of drought. In this study, we characterized the maize dsd1 (decreased stomatal density 1) mutant, which showed defects in stomatal development, including guard mother cell differentiation, subsidiary cell formation and guard cell maturation. DSD1 encodes the basic helix-loop-helix transcription factor INDUCER OF CBF EXPRESSION b (ZmICEb) and is a homolog of ICE1 in Arabidopsis (Arabidopsis thaliana). DSD1/ZmICEb is expressed in stomatal file cells throughout stomatal development and plays a conserved role in stomatal development across maize and Arabidopsis. Mutations in DSD1/ZmICEb dramatically improved drought tolerance and WUE in maize and reduced yield losses under drought conditions. Therefore, DSD1/ZmICEb represents a promising candidate target gene for the genetic improvement of drought tolerance in maize by manipulating stomatal density.

Avena barbata, a wild oat species within the genus Avena, is a widely used model for studying plant ecological adaptation due to its strong environmental adaptability and disease resistance, serving as a valuable genetic resource for oat improvement. Here, we phased the high-quality chromosome-level genome assembly of A. barbata (6.88 Gb, contig N50 = 53.74 Mb) into A (3.57 Gb with 47,687 genes) and B (3.31 Gb with 46,029 genes) subgenomes. Comparative genomics and phylogenomic analyses clarified the evolutionary relationships and trajectories of A, B, C and D subgenomes in Avena. We inferred that the A subgenome donor of A. barbata was Avena hirtula, while the B subgenome donor was probably an extinct diploid species closely related to Avena wiestii. Genome evolution analysis revealed the dynamic transposable element (TE) content and subgenome divergence, as well as extensive structure variations across A, B, C, and D subgenomes in Avena. Population genetic analysis of 211 A. barbata accessions from distinct ecotypes identified several candidate genes related to environmental adaptability and drought resistance. Our study provides a comprehensive genetic resource for exploring the genetic basis underlying the strong environmental adaptability of A. barbata and the molecular identification of important agronomic traits for oat breeding.

Plant root-associated fungal communities play a pivotal role in enhancing plant growth, nutrient absorption, disease resistance and environmental stress adaptation. Despite their importance, the assembly processes of these communities remain inadequately explored. In this study, we utilizzzed high-throughput sequencing, co-occurrence network analysis and null models to examine the diversity, composition, interaction patterns and assembly mechanisms of the root-associated fungal communities of Mussaenda pubescens, a drought-tolerant shrub that thrives in stressful environments and is widely used for Chinese medicine. Our findings revealed pronounced regional and ecological niche-based variations in the diversity and assembly of total fungi and essential functional guilds, including saprotrophs, symbiotrophs and plant pathogens. Significantly, the fungal diversity of plant pathogens decreased with elevation, whereas total fungi, saprotrophs and symbiotrophs were minimally affected. Stochastic processes, such as dispersal limitation, played a significant role in fungal assembly. Furthermore, soil physicochemical properties, climatic conditions and spatial variables emerged as critical determinants of fungal community structure. This study enriches our understanding of the dynamics governing root-associated fungal community assemblies and underscores the factors essential for sustaining fungal diversity.

This study used a method based on a spatial series in place of a temporal series, selecting Tamarix ramosissima shrubs at different developmental stages of coppice dunes as research subjects to investigate their chlorophyll fluorescence characteristics and non-structural carbohydrates (NSC). The results indicated that: (1) As coppice dunes developed, T. ramosissima showed a significant increase in photosynthetic pigment content alongside a decrease in actual photochemical efficiency (Y_(II)). Simultaneously, the reduction state of the plastoquinone (PQ) pool intensified, the apparent electron transport rate (ETR) increased, and the quantum yield of regulated energy dissipation significantly increased. These adaptations enabled T. ramosissima to dissipate excess light energy by enhancing its non-photochemical energy dissipation mechanisms. (2) Photosynthetically active radiation (PAR) and T. ramosissima leaf temperature (T_L) gradually increased during coppice dune development, whereas soil water content decreased, leading to increased stress on T. ramosissima and a subsequent decline in NSC content. This increased stress placed T. ramosissima at risk of ‘carbon starvation’, resulting in a gradual reduction in photosynthesis, biomass accumulation, and ultimately, mortality. (3) Correlations among various indicators of T. ramosissima were significant, with the highest degree of association and marked enhancement of synergistic effects in the growth and stable stages of coppice dunes. Comprehensive analysis revealed that high soil moisture content can alleviate water stress, improve light energy use efficiency and enhance the photosynthetic carbon assimilation process in T. ramosissima during coppice dune development.

The karst forest in southwestern China is characterized by thin soil layers, numerous fissures and holes, resulting in low soil water availability and poor water retention, making it challenging for plant growth and survival. While the relationship between plant functional traits and tree growth performance has been extensively studied, the links between tree seasonal growth and drought-tolerant traits in tree species with different leaf habit remains poorly understood. This study evaluated the associations between four-year averaged rainy season stem diameter growth rate and 17 branch and leaf traits across evergreen and deciduous species in a tropical karst forest in southwest China. The cross-species variations in tree growth rates were related to plant hydraulic traits (e.g., vessel lumen diameter, xylem vessel density, stomatal density, and stomatal size) and leaf anatomical traits (e.g., total leaf thickness, lower/upper epidermis thickness, and spongy thickness). The growth of evergreen trees exhibited lower hydraulic efficiency but greater drought tolerance than deciduous tree, which enabled them to maintain higher persistence under low soil water availability and consequently a relatively longer growing season. In contrast, deciduous species showed no correlation between their functional traits and growth rate. The distinct water use strategies of evergreen and deciduous trees may offer a potential explanation for their co-existence in the tropical karst forests.

Reactive oxygen species (ROS) plays critical roles in modulating plant growth and stress response and its homeostasis is fine tuned using multiple peroxidases. H₂O₂, a major kind of ROS, is removed rapidly and directly using three catalases, CAT1, CAT2, and CAT3, in Arabidopsis. Although the activity regulations of catalases have been well studied, their degradation pathway is less clear. Here, we report that CAT2 and CAT3 protein abundance was partially controlled using the 26S proteasome. To further identify candidate proteins that modulate the stability of CAT2, we performed yeast-two-hybrid screening and recovered several clones encoding a protein with RING and vWA domains, CIRP1 (CAT2 Interacting RING Protein 1). Drought and oxidative stress downregulated CIRP1 transcripts. CIRP1 harbored E3 ubiquitination activity and accelerated the degradation of CAT2 and CAT3 by direct interaction and ubiquitination. The cirp1 mutants exhibited stronger drought and oxidative stress tolerance, which was opposite to the cat2 and cat3 mutants. Genetic analysis revealed that CIRP1 acts upstream of CAT2 and CAT3 to negatively regulate drought and oxidative stress tolerance. The increased drought and oxidative stress tolerance of the cirp1 mutants was due to enhanced catalase (CAT) activities and alleviated ROS levels. Our data revealed that the CIRP1–CAT2/CAT3 module plays a vital role in alleviating ROS levels and balancing growth and stress responses in Arabidopsis.

Aims Drought effects on the carbon (C) balance are considered the major factor of tree mortality and are assumed to be regulated by soil nutrient (e.g., nitrogen (N)) availability. However, the effects of nitrogen addition on trees’ carbon and nitrogen distribution between aboveground and belowground and the coupling between carbon and nitrogen relations in various organs in response to drought are still unclear in trees.
Methods A two-year full factorial microcosm experiment was set up with sessile oak (Quercus petraea). Nitrogen addition was performed in the first year, and a drought treatment was conducted in the second year. Isotope ¹⁵N and ¹³C labelling were carried out before drought and during drought, respectively. Three consecutive samplings were conducted after the dual labelling with ¹³C and ¹⁵N in the second year, and the effects of nitrogen addition on carbon and nitrogen allocation dynamics during progressive drought were tested.
Important findings Our results showed that previous nitrogen addition promoted photosynthetic carbon fixation and nitrogen allocation, increased root nitrogen uptake, reduced the non-structural carbohydrates (NSC) contents in all organs and changed the relationships of carbon and nitrogen in aboveground and belowground organs. In contrast, drought had minor effects on nitrogen and carbon allocation between aboveground and belowground and the relationship of carbon with nitrogen in all organs (represented by the ratio of ¹³C to ¹⁵N in all organs). Drought only significantly reduced the content of NSC. During drought (from day 40 to 73), previous nitrogen addition led sessile oak to prioritise belowground carbon and nitrogen allocation. Our results indicate that sessile oak can change its carbon and nitrogen allocation strategies to adapt to drought, while previous nitrogen addition may increase its drought sensitivity.

To explore the environmental adaptation mechanisms of Caragana halodendron in leaf traits， to provide a theoretical basis for breeding superior varieties of C. halodendron， and protection of species diversity in desert areas， soil and water conservation， and desertification mitigation， the phenotypic variations among different populations and their relationships with environmental factors were analyzed respectively. The 108 individuals from 18 natural populations of C. halodendron were used as research materials， and 11 leaf-related traits and 28 environmental factors were collected. Pearson correlation analysis and principal component analysis were utilized to explore the variation patterns of leaf traits and their correlations with environmental factors. The results showed that： （1）There were remarkably significant differences in the leaf traits of C.halodendron among different populations. The variation coefficient of leaf traits ranged from 9.42% to 83.12% among the populations and 1.58% to 59.07% intra-populations. Through a detailed comparison of the variation coefficient of traits within and among populations， it was evident that the average coefficient of variation among populations（31.17%） for all traits was higher than that within populations（21.86%）. （2）Correlation analysis of leaf traits revealed significant positive correlation between traits related to leaf shape （leaf length， leaf width， leaf area， specific leaf area）（P<0.05）， and leaf water content showed a significant positive correlation with leaf shape traits（P<0.05）. （3） Four principal components extracted from trait principal component analysis accounted for a cumulative contribution rate of 91.13%. （4）The correlation analysis between leaf traits and environmental factors showed that leaf shape， rachis length， stipular spine length， and the number of leaflets were extremely significantly correlated with multiple environmental factors such as drought， precipitation， temperature， and soil（P<0.01）， whereas specific leaf area was only extremely significantly correlated with multiple environmental factors（P<0.01）. The variation in leaf traits reflects the adaptability of this species to arid and saline-alkali environments and the strategy of C. halodendron adapting to environmental pressure by adjusting traits such as leaf shape， rachis length， and leaf water content. This work provided important insights for understanding the adaptation mechanism of desert plants.

The black wolfberry (Lycium ruthenicum; 2n = 2x = 24) is an important medicinal plant with ecological and economic value. Its fruits have numerous beneficial pharmacological activities, especially those of anthocyanins, polysaccharides, and alkaloids, and have high nutritional value. However, the lack of available genomic resources for this species has hindered research on its medicinal and evolutionary mechanisms. In this study, we developed the telomere-to-telomere (T2T) nearly gapless genome of L. ruthenicum (2.26 Gb) by integrating PacBio HiFi, Nanopore Ultra-Long, and Hi-C technologies. The assembled genome comprised 12 chromosomes with 37,149 protein-coding genes functionally annotated. Approximately 80% of the repetitive sequences were identified, of which long terminal repeats (LTRs) were the most abundant, accounting for 73.01%. The abundance of LTRs might be the main reason for the larger genome of this species compared to that of other Lycium species. The species-specific genes of L. ruthenicum were related to defense mechanisms, salt tolerance, drought resistance, and oxidative stress, further demonstrating their superior adaptability to arid environments. Based on the assembled genome and fruit transcriptome data, we further constructed an anthocyanin biosynthesis pathway and identified 19 candidate structural genes and seven transcription factors that regulate anthocyanin biosynthesis in the fruit developmental stage of L. ruthenicum, most of which were highly expressed at a later stage in fruit development. Furthermore, 154 potential disease resistance-related nucleotide-binding genes have been identified in the L. ruthenicum genome. The whole-genome and proximal, dispersed, and tandem duplication genes in the L. ruthenicum genome enriched the number of genes involved in anthocyanin synthesis and resistance-related pathways. These results provide an important genetic basis for understanding genome evolution and biosynthesis of pharmacologically active components in the Lycium genus.

NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) are a family of plant-specific TFs that play crucial roles in various aspects of plant development and stress responses. Here, we provide an in-depth review of the structural characteristics, regulatory mechanisms, and functional roles of NACs in different plant species. One of the key features of NACs is their ability to regulate gene expression through a variety of mechanisms, including binding to DNA sequences in the promoter regions of target genes, interacting with other TFs, and modulating chromatin structure. We discuss these mechanisms in detail, providing insights into the complex regulatory networks that govern the activity of NACs. We explore the diverse functions of these TFs in plant growth and development processes, including embryogenesis, seed development, root and shoot development, floral development and fruit ripening, secondary cell wall formation, and senescence. We also discuss the diverse regulatory roles of NACs in response to various stresses, including drought, flooding, heat, cold, salinity, nutrient deficit, and diseases. Lastly, we emphasize the crosstalk role of NACs between developmental processes and stress responses. This integrated perspective highlights how NACs orchestrate plant growth and resilience. Overall, this review provides a comprehensive overview of the pivotal roles of NACs in plant development and stress responses, emphasizing their potential for engineering stress-resistant crops and enhancing agricultural productivity.

Plants have co-evolved with a wide range of microbial communities over hundreds of millions of years, this has drastically influenced their adaptation to biotic and abiotic stress. The rapid development of multi-omics approaches has greatly improved our understanding of the diversity, composition, and functions of plant microbiomes, but how global climate change affects the assembly of plant microbiomes and their roles in regulating host plant adaptation to changing environmental conditions is not fully known. In this review, we summarize recent advancements in the community assembly of plant microbiomes, and their responses to climate change factors such as elevated CO₂ levels, warming, and drought. We further delineate the research trends and hotspots in plant–microbiome interactions in the context of climate change, and summarize the key mechanisms by which plant microbiomes influence plant adaptation to the changing climate. We propose that future research is urgently needed to unravel the impact of key plant genes and signal molecules modulated by climate change on microbial communities, to elucidate the evolutionary response of plant–microbe interactions at the community level, and to engineer synthetic microbial communities to mitigate the effects of climate change on plant fitness.

Aims: The combined impacts of climate change and human activities are likely to increase the land areas suitable for poisonous weeds, leading to rapid biodiversity loss and increasingly severe grassland degradation in the semi-arid region of Xinjiang. Enhanced understanding of the relationship between soil biomes and ecosystem multifunctionality can provide theoretical support for efforts to control the spread of poisonous weeds in Xinjiang.
Methods: This study used a field experiment to explore the effects of nitrogen, water addition and mowing on soil biodiversity patterns, co-occurrence networks, and the relationship between diversity indices and ecosystem multifunctionality. This study adopted a randomized block trial design and set up eight treatments, which are no nitrogen, no watering, no mowing (CK), nitrogen addition (N treatment), watering (W treatment), mowing (M treatment), nitrogen × watering (NW treatment), nitrogen × mowing (NM treatment), watering × mowing (WM treatment), nitrogen × watering × mowing (NWM treatment).
Results: (1) The Shannon-Wiener diversity index of soil bacteria differed significantly between the control, water addition, and nitrogen-mowing treatments. There were no significant differences between the diversity of soil fungi, nematodes, and arthropods in each treatment. (2) N, W, M, NW, and NM treatments all resulted in reduced complexity and connectivity of soil biological co-occurrence networks. WM and NWM treatments increased the complexity and connectivity of soil biological co-occurrence networks. (3) In the control, there was a significant and positive correlation between multidiversity and ecosystem multifunctionality (P < 0.01). In the NM treatment, there was a significant and negative correlation between multidiversity and ecosystem multifunctionality (P < 0.05). There was no correlation between multidiversity and ecosystem multifunctionality in the other treatments. Finally, soil bacterial diversity was most susceptible to the change of external environment.
Conclusion: This study demonstrated that short-term nitrogen addition, watering, and mowing can weaken the relationship between soil biodiversity and ecosystem multifunctionality. These findings provide a theoretical basis for closer study of the mechanisms that affect the relationship between soil biodiversity and ecosystem multifunctionality through environmental changes caused by global climate change.

Aims Grassland plant roots and mycorrhizal fungi are the main sources of soil organic carbon, which play an important role in the formation and turnover of soil organic carbon and its components, and they also affect the soil nitrogen pool. Under the scenario of climate change, global drought events are frequent. How drought affects the role of roots and mycorrhizal fungi on soil carbon and nitrogen pools of different components is still unclear.
Methods In this study, Cleistogenes squarrosa was planted in indoor pots and subjected to control and drought treatments. Root bags and mycorrhizal bags were set up to distinguish the effects of plant roots and mycorrhizal fungi on the carbon and nitrogen content of soil organic matter and its components during plant growth. After 64 days of plant growth, the plants were harvested. The soil inorganic nitrogen content, plant biomass, plant leaf carbon and nitrogen content, carbon and nitrogen content of soil organic matter and its components in root bags and mycorrhizal bags, and microbial community composition were measured.
Important findings The results showed that compared with mycorrhizal bags without root participation, the soil organic carbon and particulate organic carbon content in the root bags enhanced by 17.5% and 55.8%, and the mineral-associated organic nitrogen content increased by 10.1%. Drought treatment increased soil inorganic nitrogen content, reduced plant biomass, had no significant effect on the carbon and nitrogen content of soil organic matter and its components in the root bag, but significantly reduced the content of particulate organic carbon in the mycorrhizal bag. Drought treatment did not significantly change the microbial biomass in the root bag, but increased the microbial biomass in the mycorrhizal bag. The particulate organic carbon content in the mycorrhizal bags was negatively correlated with the amount of mycorrhizal fungi and the total microbial biomass. The results showed that during plant growth, the roots mainly affected the content of particulate organic carbon in the soil, and mycorrhizal fungi mainly affected the content of mineral-associated organic nitrogen. Short-term drought reduced the content of particulate organic carbon in the soil where mycorrhizal fungi were present. Future research should pay more attention to how global change affects the relative contributions of grassland plant roots and mycorrhizal fungi to soil organic matter and its components and their potential impact on soil organic carbon and nitrogen on a long-term scale.

INTRODUCTION: 14-3-3 proteins are a highly conserved protein family that specifically recognize phosphorylated target proteins and play crucial roles in plant abiotic stress responses. By interacting with AREB/ABF (ABA-responsive element binding protein/ABA-responsive element binding factor) transcription factors, 14-3-3 proteins participate in ABA signal transduction and regulate abiotic stress tolerance. TaGRF3-D is a 14-3-3 protein gene in wheat (Triticum aestivum), and our previous studies revealed that the expression of this gene was upregulated under ABA and abiotic stress.
RATIONALE: To explore the biological function of the TaGRF3-D gene, we cloned the gene, and investigated its subcellular localization and function under drought stress.
RESULTS: The results revealed that TaGRF3-D is highly conserved in monocotyledonous plants and is localizes in the nucleus and plasma membrane. Compared with the wild type, the Arabidopsis thaliana transgenic lines overexpressing TaGRF3-D presented significantly longer roots under PEG and ABA treatments and showed a markedly greater survival rate after drought stress. Yeast two-hybrid analysis revealed that TaGRF3-D interacted with wheat TaABF3-B, TaABF4-A, TaABF15-D, TaABF16-B, TaABF17-D, and TaABF18-B, but not with TaABF1-D, TaABF2-A or TaABF19-A.
CONCLUSION: These results suggest that TaABF3-D responds to ABA signaling by interacting with wheat TaABF transcription factors, thereby increasing the drought stress tolerance of transgenic plants.

Phenotypes of the TaGRF3-D transgenic lines and the wild type (WT) under drought stress (A) and interaction between the TaGRF3-D protein and the ABF protein (B). Bars=1 cm

The ecologically fragile arid valleys in western China have low afforestation survival rates, and the lack of adaptable superior variety is key to restricting forestry production and ecological restoration in this region. The native poplar trees are important germplasm resources in this region, with a wide range of taxa, rich genetic variations, and great potential for breeding and utilization. Six clones of native poplars were used in a field trial to investigate variations in survival, growth and adaptation to arid-warm and arid-hot valleys. In the arid-hot valley, clone Y1-2 exhibited the highest survival rate and growth condition, surpassing other clones, while clones B7-4 and P3-6 demonstrated superior survival and growth performance in the arid-warm valley. Clone B7-4 displayed the highest soluble sugar content in leaves across both habitats. Superoxide dismutase and ascorbate peroxidase activities, along with malondialdehyde content in leaves, were higher in the arid-hot valley for all clones compared with the arid-warm valley. Long-term water use efficiency, as indicated by δ¹³C in leaves, was significantly higher for all clones in the arid-hot valley, particularly for H1-6, T3-2 and P3-6. Increases in upper epidermis thickness were observed in clones E1, B7-4 and P3-6, while Y1-2 exhibited a higher palisade parenchyma thickness (PT) in the arid-hot valley compared with the arid-warm valley. Vein densities were higher in leaves of clones E-1, B7-4, Y1-2 and P3-6 in both valleys compared with other clones, with B7-4 showing a significant increase in mean vein width in the arid-hot valley. In conclusion, the superior growth performance of clone B7-4 in the arid-warm valley may be attributed to its stronger osmotic adjustment and higher capacity to maintain water transportation through venation. The exceptional performance of clone Y1-2 in the arid-hot valley may be associated with its compact arrangement of PT, as well as its stronger capacity for hydraulic transport and antioxidant resistance in leaves.

Trade-offs have long been recognized as a crucial ecological strategy for plant species in response to environmental stresses and disturbances. However, it remains unclear whether trade-offs exist among different structures (or functions) of clonal plants in response to aeolian activities in sandy environments. We examined the growth (reproductive vs. vegetative), reproduction (sexual vs. asexual), and bud bank (tiller buds and rhizome buds, representing vertical and horizontal growth potential) characteristics of two dominant rhizomatous grasses (Psammochloa villosa and Phragmites australis) in the arid sand dunes of northwestern China. Our results showed that these two rhizomatous clonal species exhibited significant trade-offs in their adaptation strategies in response to changes in sand burial depth. Specifically, as sand burial depth increased, the clonal species tended to reduce their reproductive growth, sexual reproductive capacity, and horizontal growth potential, as evidenced by reductions in reproductive ramet number and proportion, panicles number, biomass, and their proportions, as well as rhizome bud number, biomass, and their proportions. Conversely, they increased vegetative growth, reproduction, and vertical growth potential, as evidenced by enhancements in vegetative ramet number and proportion, belowground bud number, biomass, and their proportions, and in tiller bud number, biomass, and their proportions. Our study underscores the importance of trade-offs in the adaptation strategies of rhizomatous clonal species in sandy environments where drought stress and aeolian disturbance coexist. Those trade-offs could ensure the population persistence and stability of pioneering psammophytes in sand dunes, which should be considered during sand-fixing and vegetation restoration efforts in arid sand dunes.

Aims Changes in precipitation characteristics, such as drought, prolonged dry season, and increased dry-wet alternation, lead to variations in plant functional traits. These changes trigger adjustments in the cooperative relationship of plant functional traits within a single organ or between multiple organs. Consequently, plant behavior and adaptation strategies change accordingly. However, the quantitative relationships and mechanisms behind this process are still unclear. This study aims to measure the specific responses of common species to climate across regions along a precipitation gradient, quantify the trait-environment relationship, elucidate the regulatory mechanism, and reveal the regional differentiation of functional traits and adaptation strategies of common species. This study will provide data support and solid scientific basis for climate management.

Methods The study focused on Ulmus pumila as the experimental subject. Ten sites were selected along a precipitation gradient from southeast to northwest China, where 28 functional traits of branches and leaves were measured. We analyzed the regional differentiation of branch and leaf traits, as well as their trade-offs. Furthermore, we quantified the regional differentiation of collaborative relationships among functional traits of branches and leaves along the precipitation gradient, revealing the adaptation strategies of U. pumila to varying moisture environments.

Important findings The results showed that: (1) In humid regions, U. pumila branches exhibited the highest hydraulic conductivity (K_s) and the lowest cavitation resistance (P₅₀); as precipitation decreased, leaf thickness and leaf tissue structure tightness increased, enhancing U. pumila’s drought resistance. (2) Across the entire precipitation gradient, there was an efficiency-safety trade-off within branches and between branches and leaves of U. pumila; however, at the regional scale, this trade-off relationship decoupled with decreasing precipitation. (3) Correlation analyses of branch and leaf functional traits revealed that, across the entire precipitation gradient, maximum net photosynthetic rate (P_n) and leaf mass per unit area were negatively correlated with K_s and positively correlated with P₅₀. Ulmus pumila regulated photosynthesis through coordinated adjustments of branch water transport capacity and leaf functional traits. The coordination and adjustment of branch and leaf functional traits are crucial mechanisms for U. pumila to adapt to varying moisture environments.

With the global increase in tree mortality events caused by drought, there have been numerous reports on the mechanism of drought-induced tree mortality both domestically and internationally in recent years. However, the exact mechanism that causes tree mortality remains unclear, which increases the uncertainty of predicting the survival probability of forests under future climate changes. This review systematically analyzed the research progress related to tree death caused by extreme drought events, focusing the prediction of death point and physiological mechanism of drought-induced tree mortality. It highlighted that tree death was the result of multiple physiological processes. Furthermore, previous reports have shown that the death judged by visual symptoms may occur after the tree has already been dead for a period, leading to a lack of early warning signals and making the death inevitable. The review analyzed the main characteristics and possible sequence of physiological variables such as the degree of xylem embolism, radial flow, cell membrane permeability, and cambium activity in the process of drought-induced tree mortality. It suggests that the loss of cambium activity ultimately led to irreversible tree death. Therefore, when discussing the mechanism of drought-induced tree mortality, quantifying the loss rate of cambium activity is crucial for accurately determining the time of tree death, which is worth further studying. This paper also proposed relevant issues and research directions in the field of drought-induced tree mortality, providing reference ideas for accurately predicting tree death and formulating efficient and appropriate solutions to future climate change.