Search Results (1,258)

Drought is one of the major abiotic stresses limiting soybean production, and its detrimental effects are jointly influenced by stress intensity, duration, and cultivation conditions. To investigate the morphological and physiological regulatory mechanisms by which mepiquat chloride (DPC) alleviates drought stress at the soybean seedling stage, this study used the drought-tolerant soybean cultivar Heinong 44 (H-44) and the drought-sensitive cultivar Heinong 65 (H-65) as experimental materials. Osmotic stress was simulated with 10% PEG-6000 at the V2 stage, and the effects of foliar application of different DPC concentrations (125–500 mg/L) on soybean morphology, biomass allocation, antioxidant systems, and osmotic adjustment capacity were systematically analyzed. The results showed that drought stress significantly inhibited the growth of both soybean cultivars and induced severe oxidative damage. Appropriate DPC concentrations moderately restricted shoot growth to reduce transpiration area while promoting root growth to enhance water acquisition capacity. The optimal DPC concentrations for alleviating drought stress were 200 mg/L for H-44 and 275 mg/L for H-65. Allometric growth analysis indicated that drought disrupted the original root–shoot growth pattern, whereas appropriate DPC concentrations significantly promoted dry matter accumulation in drought-stressed plants and improved root–shoot growth coordination. However, an excessive concentration of DPC (500 mg/L) caused an abnormal deviation in the growth trajectory. In addition, appropriate DPC concentrations synergistically enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in leaves and roots under drought conditions; promoted the accumulation of proline (Pro), soluble sugars (Ss), and soluble proteins (Sp); effectively reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂); and protected cell membrane stability. In conclusion, DPC synergistically enhances drought resistance in soybean by reshaping the root–shoot allometric growth configuration and systematically activating physiological defense networks, providing a theoretical basis for chemically regulated cultivation of soybean under stress conditions. Full article

Increasingly frequent and severe drought events restrict global agricultural productivity. As sessile organisms, cereal crops have evolved phenotypic plasticity, drawing on drought escape (DE) and drought avoidance (DA) strategies to balance survival and reproduction. While the mechanisms governing photoperiodic flowering and drought responses are well characterized individually, their molecular intersection remains poorly understood. This review summarizes recent advances in the crosstalk between these two pathways. We highlight the divergent roles of core genetic hubs, such as florigen regulation, GIGANTEA (GI), DELLA proteins, and dual-function transcription factors (e.g., ZmCCT, Ghd7, Ppd-H1), and the breeding-selected alleles, including Green Revolution variants, that can partly uncouple stress tolerance from developmental penalties, though trade-offs often remain. Furthermore, we examine the internal networks driving this crosstalk, including circadian clock phase shifts, sugar and energy signaling through the trehalose-6-phosphate (T6P)-SNF1-related protein kinase 1 (SnRK1) module, and the antagonistic balance within phytohormone networks centered on abscisic acid (ABA). Finally, we propose that integrating epigenetic stress memory, systemic root-to-shoot signaling, and targeted CRISPR/Cas promoter engineering provides a useful conceptual framework for breeding climate-resilient, yield-stable crops. Full article

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, but its yield and quality improvement are often constrained by drought stress. To investigate the physiological and molecular mechanisms by which exogenous allantoin enhances drought tolerance in cucumber, cucumber seedlings were sprayed with 6 mM allantoin solution once (A1), three times (A3), or five times (A5), while control plants were sprayed with distilled water (CK1, CK3, CK5). Each treatment consisted of three biological replicates. After treatment, drought stress was simulated by irrigating with 20% polyethylene glycol 6000 (PEG-6000) solution. The results showed that the protective effect of exogenous allantoin against drought stress was cumulative. After five applications (A5), the net photosynthetic rate (Pn) and water-use efficiency (WUE) of the plants were significantly higher than those of the corresponding control (CK5) (p < 0.01). The detached leaf water loss rate progressively decreased with an increasing number of allantoin applications, while the total leaf wax content increased approximately 2-fold (p < 0.01). Measurements of wax content in different plant tissues indicated that allantoin mainly induced wax accumulation in aboveground organs (leaf, stem, and fruit epidermis), and this effect was validated in three commercial varieties. Integrated transcriptomic and metabolomic analyses revealed that the cucumber CsCER1 gene (encoding a very-long-chain aldehyde decarbonylase) is a core allantoin-responsive gene. After silencing CsCER1 using virus-induced gene silencing (VIGS), the allantoin-induced wax accumulation and drought tolerance were almost completely lost: the wilting severity and detached leaf water loss rate of the silenced plants were comparable to those of the empty vector control, and no significant increase in wax content was observed. This study reveals a novel mechanism by which exogenous allantoin enhances drought tolerance in cucumber through activating CsCER1-mediated cuticular wax synthesis, providing a theoretical basis for the chemical regulation of drought tolerance in cucurbit crops. Full article

Abiotic stresses severely restrict plant growth, development, and crop yield. Histone modification functions as a key epigenetic regulator in plant stress adaptation. This review systematically summarizes the major types of histone modifications (e.g., acetylation, methylation) and their catalytic enzyme systems. It clarifies the regulatory patterns of chromatin remodeling and gene expression under diverse abiotic stress conditions, like extreme temperature changes, persistent drought, elevated salinity, and heavy metal exposure, and reveals the crosstalk networks between histone modifications and ABA, CBF/DREB, and ROS signaling pathways. It also discusses the transgenerational inheritance of stress-induced histone modification variations and their molecular basis, and introduces the application of CRISPR/Cas9 and dCas9-based epigenetic editing in improving crop stress resistance. Currently, research on histone modification in plateau crops remains fragmented: studies mostly focus on single stress rather than combined multiple abiotic stresses, lack tissue-specific epigenetic regulatory maps for native plateau plants, and the field application of epigenetic breeding technologies is seriously insufficient. Considering the compound stresses, including low temperature, drought, salinization, and heavy metals, on the Qinghai–Tibet Plateau, this review identifies current research gaps, such as tissue specificity, multi-stress crosstalk, and field application, and proposes future directions, including multi-omics analysis, stress adaptation mechanisms of plateau plants, and precise epigenetic breeding. Overall, this review fills the research gap of systematic collation on histone-mediated stress tolerance epigenetics under plateau combined abiotic stresses, and provides a theoretical reference for epigenetic research on plant stress resistance and for the improvement of plateau crops. Full article

Protein nitration within the nitro-proteome is a dynamic component of drought and recovery responses in wheat (Triticum aestivum L.), yet its role in stress adaptation remains unclear. Young wheat seedlings demonstrate a degree of drought resistance, characterized by physiological and morphological adaptations, during the initial growth phases. However, this tolerance begins to diminish significantly in 5-day-old seedlings. The mechanisms behind this phenomenon are unclear. Our results indicate that it may be related to protein nitration. This study compared the physiological and nitrosative responses of 4-day-old drought-tolerant and 6-day-old sensitive wheat seedlings subjected to drought followed by rehydration. In tolerant seedlings, in contrast to sensitive ones, the water saturation deficit after rehydration returned to the control levels, confirming their drought tolerance. Moreover, NO₂⁻ accumulation in the recovery group was significantly higher in sensitive seedlings than in the control group. Results indicate that drought resistance correlates with protein nitration during the recovery phase. Nitro-proteomic analysis revealed that in tolerant seedlings, protein nitration is limited. The most significant differences are observed in the recovery group, with predominant downregulation of protein nitration in tolerant seedlings and significant upregulation of numerous proteins in sensitive seedlings. Upregulated nitration of vital proteins involved in energy production, photosynthesis (such as the Rubisco large subunit), ATP synthases, and cytosolic malate dehydrogenase may lead to disturbances in energy metabolism and thus prevent an effective response to changing environmental conditions. These findings suggest that regulation of protein nitration during recovery may contribute to drought resilience in wheat and could represent a potential target for improving stress tolerance. Full article

Driven by increasingly severe drought stress associated with global warming, this study investigated a synthetic microbial community, SynCom-SASW01, with strong stress tolerance and plant growth-promoting potential, and systematically elucidated its mechanisms for enhancing drought resistance in wheat (Triticum aestivum L.). Dual-site field trials demonstrated that SynCom-SASW01 significantly alleviated drought-induced growth suppression, increasing grain yields by 10.42% and 8.52% at the Hohhot and Hulunbuir sites, respectively. This improvement was primarily associated with increased effective tiller number and enhanced root vigor. Physiologically, inoculation promoted root proline and glutathione accumulation and enhanced antioxidant enzyme activities, including superoxide dismutase, thereby reducing malondialdehyde levels. Environmental analyses showed that the consortium established rhizosphere “micro-reservoirs” through exopolysaccharide secretion, improving soil relative water content and the availability of alkali-hydrolyzable nitrogen and phosphorus. High-throughput sequencing revealed that SynCom-SASW01 reshaped the endosphere microbiome through early colonization priority effects, selectively enriching beneficial taxa such as Pseudomonas. Functional prediction indicated upregulated branched-chain amino acid biosynthesis, promoting osmotic adjustment and redox homeostasis. These findings provide a microbiome-based strategy for stabilizing wheat productivity in arid regions. Full article

Abiotic stresses, including drought, salinity, alkalinity, temperature extremes, flooding, heavy metals, and emerging pollutants, challenge plant growth and productivity by disturbing water relations, ion balance, redox homeostasis, membrane stability, energy metabolism, and developmental progression. Although substantial progress has been made in the identification of stress-responsive hormones, second messengers, kinases, transcription factors, transporters, and metabolic regulators, plant stress adaptation cannot be fully explained by linear signaling cascades or single tolerance genes. A major unresolved question is how early molecular events are reorganized into coordinated physiological and developmental outputs that support survival, recovery, and productivity. In this review, we propose an intermolecular interaction-driven adaptive remodeling framework for plant abiotic stress responses. This framework emphasizes that stress tolerance emerges from dynamic changes in receptor–ligand recognition, protein–protein interactions, calcium decoding, redox-sensitive modification, phosphorylation networks, transcriptional regulation, chromatin-associated control, and metabolite-mediated feedback. We further emphasize ROS as integrative redox switches that connect stress sensing, defense activation, senescence-related transitions, and recovery, and chromatin-associated mechanisms as regulators that may stabilize primed or memory-like adaptive states. We discuss how these interaction networks converge on core signaling hubs, including abscisic acid, reactive oxygen species, Ca²⁺, and kinase/phosphatase systems, and how they remodel stomatal behavior, root architecture, ion and pH homeostasis, redox buffering, metabolism, development, and reproductive resilience. We further highlight how natural variation, multi-omics, genome editing, high-throughput phenotyping, and field validation can translate interaction-centered stress biology into crop resilience. This perspective provides a conceptual bridge between molecular stress perception, network behavior, physiological adaptation, and climate-resilient agriculture. Full article

Extreme climatic conditions often intensify abiotic stress factors (such as drought, salinity, heat stress, ultraviolet radiation, and soil degradation), and are increasingly limiting crop productivity and threatening global food security. Secondary metabolites (SMs), traditionally viewed as defense compounds, are now recognized as key regulators of plant adaptation to environmental stress. This review synthesizes recent advances in understanding the role of SMs as biochemical targets for improving crop resilience to climate extremes. By integrating evidence from multi-omics studies, artificial-intelligence-driven analyses, and functional genomics, we examine how stress-specific metabolic signatures and regulatory networks can be exploited for crop improvement. We further discuss the application of genome editing, synthetic biology, and metabolomics-assisted breeding to modulate the SM pathways to enhance stress tolerance. Selected case studies highlight the contribution of flavonoids, alkaloids, and terpenoids to stress adaptation in major and underutilized crops grown under salinity, drought, and low-temperature conditions. Despite significant progress, challenges remain, including metabolic trade-offs between stress tolerance and yield, regulatory constraints, and public acceptance of genetically engineered crops. By linking molecular mechanisms with applied strategies, this review provides a conceptual framework for leveraging secondary metabolism in climate-resilient agriculture and identifies key gaps to guide future research and innovation. Full article

Farmer Producer Organizations (FPOs) have gained increasing attention as institutional mechanisms for improving the resilience of smallholder farming systems under changing climatic conditions. This study examines the role of FPOs in promoting the adoption of Climate-Smart Agriculture (CSA) practices, improved irrigation strategies, and sustainable land management in the arid region of Pali district, Rajasthan, India. A comparative assessment was conducted between FPO-associated member and non-member farmers to evaluate differences in climate change perception, adoption behaviour, and adaptive capacity. The study employed a mixed-methods research design using primary data collected from 408 farm households through structured interviews, focus group discussions, and key informant consultations. Descriptive statistics, mean comparison tests and regression analysis were used to examine adoption patterns and identify the major factors influencing farmers’ responses to climate risks. The findings indicate that delayed rainfall, rising temperatures, and increasing drought frequency are widely perceived by farmers as major threats to agricultural production. FPO membership was associated with higher levels of climate-risk awareness and greater reported adoption of CSA practices; however, these findings should be interpreted as associations rather than causal effects. Farmers linked with FPOs reported stronger uptake of improved and stress-tolerant crop varieties, crop diversification, mixed farming systems, agroforestry, soil moisture conservation, rainwater harvesting, improved irrigation methods, and integrated pest management practices. Education, farm size, access to extension services, market linkages, and climate information were also found to significantly influence adoption decisions. The study highlights the important contribution of FPOs in reducing transaction costs, improving access to inputs, technical knowledge, credit and markets, and encouraging collective responses to climate stress. Strengthening FPO governance, expanding extension support, and targeting vulnerable farmer groups can substantially enhance climate resilience and support sustainable agricultural transitions in arid regions. The findings demonstrate that farmer organizations can serve as effective intermediary institutions linking household-level adaptation strategies with broader goals of irrigation efficiency, land management, and rural sustainability. Full article

Studies aimed at identifying genotypes tolerant to water deficit are essential for the development of superior plant materials adapted to regions with limited water availability, such as the Brazilian Semi-Arid. This study evaluated the physiological, biochemical, and enzymatic responses of Stylosanthes spp. subjected to different levels of water availability (60%, 40%, and 20% of pot capacity). The experiment was conducted using a completely randomized design using a 3 × 2 factorial scheme, comparing the accession BGF 11-001 and the cultivar BRS-Bela (cv. Bela). Physiological traits, biochemical variables, and antioxidant enzyme activity were analyzed. The accession BGF 11-001 showed resilience under water deficit, maintaining high chlorophyll content even under severe stress. This response was associated with increased accumulation of amino acids such as proline, as well as enhanced antioxidant activity, indicating a tolerance mechanism based on osmotic adjustment and cellular protection. In contrast, cv. Bela exhibited higher sensitivity to water stress, with a pronounced reduction in photosynthetic pigments and greater accumulation of compatible solutes, including total soluble proteins, reducing sugars, amino acids, and proline, without significant activation of antioxidant enzymes. Overall, the results demonstrate that the genotypes adopt distinct strategies to cope with water stress, with BGF 11-001 being more efficient in activating defense mechanisms. Therefore, BGF 11-001 has agronomic potential for cultivation in drought-prone regions and is a promising genetic resource for forage breeding programs aimed at improving drought tolerance. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article

Sweet sorghum, a high-quality forage and energy crop, is significantly affected by drought, the primary abiotic stress impacting its growth. Melatonin (MT) has emerged as a crucial signaling molecule in plant responses to abiotic stress. This study investigates the role of melatonin in enhancing drought tolerance in sweet sorghum, specifically using the ‘Dali Shi’ variety under polyethylene glycol (PEG)-induced drought conditions. Our findings demonstrate that exogenous melatonin application significantly increased proline content (by 27.76% and 5.95% under mild and moderate drought, respectively) while decreasing malondialdehyde (MDA) levels (by 18.33% and 35.18%, respectively). Melatonin also enhanced the accumulation of photosynthetic pigments, including chlorophyll b and total chlorophyll, and improved photosynthetic fluorescence parameters (Fv/Fm and ETR). Additionally, melatonin treatment improved root vitality, stimulated carbon and nitrogen metabolism, and increased antioxidant enzyme activity. Transcriptomic analysis revealed that differentially expressed genes were enriched in pathways related to carbon fixation, glycolysis/gluconeogenesis, nitrogen metabolism, antioxidant defense, and plant hormone signaling. Notably, melatonin upregulated key genes associated with these pathways and activated bHLH and MYB transcription factors. In conclusion, this study elucidates the mechanisms by which melatonin enhances sweet sorghum’s drought tolerance, highlighting its potential as a practical approach for improving drought resistance in this crop. Full article

Plants are constantly exposed to diverse abiotic stresses, including drought, salinity, and extreme temperatures, which severely limit growth, development, and crop productivity. These stresses disrupt physiological, biochemical, and molecular processes, leading to reduced photosynthesis, altered water and ion homeostasis, and accumulation of reactive oxygen species (ROS). Plants have evolved sophisticated sensing and signaling mechanisms to perceive these stresses, with phytohormones playing central roles in mediating adaptive responses. Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (IAA), ethylene (ET), melatonin, and strigolactones (SLs), regulate stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression. Importantly, these hormones operate within an intricate network of crosstalk, integrating multiple signaling pathways to balance growth and stress adaptation. Interactions among ABA, GA, JA, SA, auxin, ET, SLs, and melatonin enable plants to coordinate transcriptional regulation, protein phosphorylation, and ROS signaling, optimizing survival under fluctuating environmental conditions. Understanding the molecular mechanisms underlying hormonal crosstalk and their roles in abiotic stress tolerance provides valuable insights for developing resilient crops in the face of climate change. Full article

Wheat (Triticum aestivum L.), a key grain food crop worldwide, faces increasing threats from combined abiotic stresses exacerbated by climate change. However, the comprehensive effects of drought, salinity, and high-temperature pressure on wheat seedlings remain poorly understood. Using the cultivar “Yannong 1212”, we conducted hydroponic experiments to investigate the physiological, morphological, antioxidant, osmoregulatory, membrane lipid peroxidation, and molecular responses of wheat seedlings to single and combined stresses, and then conducted multivariate statistical analyses. The results showed that drought or salt stress inhibited seed germination in a concentration-dependent manner. However, the combined stresses significantly inhibited germination and seedling growth, leading to leaf chlorosis, chlorophyll degradation, stomatal closure, and chloroplast damage. Physiologically, the combined effect of multiple stresses induced excessive ROS and MDA accumulation, promoted proline and soluble sugar synthesis, and triggered the dynamic responses of antioxidant enzymes. Drought stress increased SOD, POD, and CAT activities, whereas salt stress had the opposite effect, and combined stresses further increased SOD and POD activities, but reduced CAT activity. Additionally, stress-responsive genes were rapidly upregulated. Multivariate analyses confirmed that the combined stress of drought and heat was the most damaging. These findings explain the synergistic damage mechanisms of combined stresses, providing a theoretical basis for genetic improvement of wheat’s stress tolerance. Full article

In this study, we investigated how substrate moisture content affects the growth performance and adaptive responses of Myriophyllum aquaticum. Through a controlled simulation experiment, we systematically analyzed the morphological characteristics and physiological responses of plants under five moisture levels: 0–15%, 15–30%, 30–45%, 45–60%, and 60–75%. The results indicate that optimal growth of M. aquaticum occurred at a substrate moisture content of 60–75%, with significant increases in plant height, branching ability, and biomass. A drought acclimation response was triggered at moisture levels ≤45%, characterized by shortened root length, increased total senescent internode length, biomass allocation shift toward aboveground parts, decreased chlorophyll a content, and elevated accumulation of malondialdehyde. Plants died at moisture levels ≤15%. However, they survived at 15–30% moisture, although their biomass continued to decline. A key finding was that under conditions where the sediment surface lacked water but the substrate moisture remained at 60–75%, plants achieved efficient water utilization and canopy reconstruction through rapid root extension and stem node proliferation, and the relative growth rate was significantly higher than that of the drought group (≤45% moisture). This strong adaptive capacity under specific water conditions, combined with its dehydration tolerance, suggests that M. aquaticum could potentially have a competitive advantage over native submerged plants that rely on stable water bodies, particularly in hydrologically fluctuating habitats. This study revealed that morpho-physiological plasticity driven by water gradients may be a key mechanism contributing to the invasive potential of M. aquaticum, providing new insights into its possible expansion potential in zones with fluctuating water levels. Full article