Search Results (4,036)

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

Water scarcity is increasingly recognized as a slow-onset ecological crisis with major environmental, socio-economic and governance effects, yet systematic assessments of how research on this topic has evolved remain limited. This study addresses this gap through a bibliometric and thematic analysis of water-scarcity publications from 2000 to 2025, using VOSviewer (version 1.6.20), Biblioshiny™ (Bibliometrix version 4.3.1) and RStudio (version 2024.12.1 + 563) to map research trends, conceptual clusters and leading contributing countries, institutions and authors. The analysis shows that water scarcity research is organized around four dominant themes: adaptive water management and climate resilience, plant physiological responses to drought and water stress, ecosystem resilience and biodiversity under water scarcity, and water-limited agriculture and food security. Early scholarship focused heavily on biophysical processes such as drought tolerance and hydraulic conductivity, while recent studies increasingly incorporate socio-ecological, governance and policy dimensions, reflecting a shift toward holistic, solution-oriented approaches. Overall, the study provides a comprehensive overview of the evolution and global distribution of water scarcity research, highlighting the importance of integrating biophysical knowledge with human-centered strategies to support evidence-based decision-making, strengthen inclusive water governance, and enhance socio-ecological resilience in the face of a changing climate. 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

The Hsp20 protein family, essential in heat stress responses across all organisms, is part of the heat shock protein (Hsp) superfamily, recognized for its conserved alpha-crystallin domain (ACD). Hsp20s are the smallest proteins in the superfamily and primarily assist in protein refolding during stress and developmental processes. We present an in silico characterization of the Hsp20 gene family in Chenopodium quinoa (2n = 4x = 36) using an integrative approach. Quinoa is well known for its global contributions to food production and tolerance to various abiotic stresses. We identified 69 CqHsp20 genes that exhibit a well-conserved evolutionary pattern, characterized by a balanced copy number distributed symmetrically across 19 homeologous pairs in both subgenomes (A and B), with localized expansions driven by tandem duplications on eight chromosomes. High sequence identity in contiguous gene pairs and Ka/Ks ratios consistently below 1 (0.14–0.84) mathematically demonstrate that strict purifying selection has maintained the structural and sequence integrity of these genes since the ancestral polyploidization event. The phylogenetic analysis grouped CqHsp20 into two main clusters, splitted into four sub-clusters based on peptides’ cellular localization, consistent with a characteristic gene structure and conserved motif analysis, which may reflect the evolutionary trajectory and functional specialization of the Hsp20 family in plants. The integration of transcriptomic data from published experiments enabled us to detect a cluster of putatively ubiquitously expressed CqHsp20, as well as other groups that showed differential responses across abiotic stress conditions. The pattern shows that more genes exhibit higher transcription abundance under drought and salinity than under heat, key adaptive traits underlying quinoa’s known ecological versatility. Some of these genes, which are undetectable or have low abundance under heat stress, encode organelle-targeting peptides, a phenomenon not reported in other model plant studies. Differential expression analysis revealed a highly transcribed sub-cluster where six out of seven of nuclear CqHsp20 genes were active in aerial tissue during initial heat stress, with a specific cohort of four genes (CQ025082, CQ031384, CQ041158, and CQ055373) maintaining significant upregulation ($|{log}_2\mathrm{Fold}\mathrm{Change}|\ge 1.0$, $\mathrm{padj}<0.05$) under prolonged and simultaneous shoot/root exposure. Varying expression within CqHsp20 homologous and paralogs supports the idea that gene duplication creates genomic diversity, facilitating adaptation to variable extreme environments. However, while theoretical and in silico analysis provide valuable insight into quinoa Hsp20 response, empirical data are essential to unequivocally understand how these gene expression variations affect quinoa response to abiotic stressors. 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

Rapeseed (Brassica napus L.) growth and productivity are severely constrained by drought stress worldwide. Stomata are central regulators of plant transpiration and gas exchange, and therefore, represent key targets for enhancing water-use efficiency and drought tolerance. The transcription factor ABSCISIC ACID INSENSITIVE 4 (ABI4), a key regulator of the abscisic acid (ABA) signaling pathway, plays crucial roles in plant abiotic stress responses and stomatal regulation. Nevertheless, the biological functions of BnaABI4 in B. napus remain largely unclear. In this study, four BnaABI4 paralogs were identified in the elite rapeseed cultivar ZS11 through genome-wide identification and comprehensive bioinformatic analyses. Each BnaABI4 protein harbors only one conserved AP2 domain, and their promoters contain multiple stress/hormone-responsive cis-regulatory elements (CREs). We subsequently generated BnaABI4-4 overexpression (OE) lines as well as BnaABI4 CRISPR/Cas9-mediated knockout (KO) transgenic lines. Phenotypic assays demonstrated that OE line had reduced transpiration rate (Tr), stomatal conductance (Gs) and stomatal density, along with enhanced drought tolerance, whereas KO lines showed the opposite phenotype. Transcriptome profiling identified numerous differentially expressed genes (DEGs) enriched in biological pathways associated with stomatal regulation, ABA signal transduction, and drought acclimation. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses confirmed significant enrichment of DEGs in processes including stomatal development, stomatal movement, reactive oxygen species (ROS) homeostasis, and drought tolerance. Collectively, our findings demonstrate that BnaABI4 negatively regulates stomatal density while positively contributing to drought tolerance in B. napus. This study lays a mechanistic foundation for genetic improvement and molecular breeding of drought-tolerant rapeseed cultivars. Full article

Agroecosystems are perpetually subjected to environmental factors. Driven by a shifting global climate, soil moisture deficits represent an increasingly frequent threat to crop productivity. In farming, however, these abiotic stressors seldom occur in isolation, as fields are invariably compounded by biotic weed pressure. Consequently, investigating plant responses to such combinatorial, multi-faceted stress is paramount to evaluating the realistic efficacy of modern agrotechnical interventions. A 2-year, three-factor pot experiment was conducted at the Research and Education Station in Swojczyce, belonging to the Wrocław University of Environmental and Life Sciences. The aim of the study was to examine the response of winter wheat (Triticum aestivum L., cv. Agil) to drought stress during the period when cereal plants were at the 51–65 BBCH developmental stages. Additionally, in some pots with winter wheat, Apera spica-venti (L.) Beauv. was sown as a weed to evaluate the effects of biotic stress. To observe the mitigation of stressors, three different types of biostimulants were used—a silicon-based preparation and two seaweed-based preparations derived from Ecklonia maxima (Osbeck) Papenfuss and Ascophyllum nodosum (L.) Le Jolis, respectively, representing structural, morphological, and biochemical defense strategies. Drought stress significantly and negatively affected the length of the wheat main stem, lateral tillers, and lateral spikes, as well as the weight of the main wheat spike. The simultaneous occurrence of drought stress and A. spica-venti competition resulted in the greatest cumulative reduction in main spike weight. Furthermore, drought stress was associated with an increase in nitrogen/protein content and potassium content in wheat straw. The presence of A. spica-venti significantly reduced both the weight of the main wheat spike and the number of non-productive tillers. The limited effectiveness of biostimulants may be associated with the severity and timing of stress exposure during reproductive development. Full article

Flavonoids play critical roles in plant adaptation to abiotic stress by acting as potent antioxidants that regulate reactive oxygen species (ROS) homeostasis. In Atriplex canescens (Pursh) Nutt., a halophytic shrub well-adapted to saline and arid environments, transcriptomic analyses revealed that salt stress induces strong upregulation of flavanone 3-hydroxylase (F3H), a key enzyme in the flavonoid biosynthetic pathway. However, the functional role of AcF3H in stress adaptation remains poorly understood. Here, we cloned the AcF3H gene from A. canescens and generated transgenic Arabidopsis thaliana (L.) Heynh. lines constitutively overexpressing this gene. Overexpression of AcF3H significantly enhanced flavonoid accumulation, as confirmed by DPBA staining and total flavonoid quantification, and selectively upregulated the expression of downstream biosynthetic genes AcDFR and AcANS, which encode the dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS), respectively. Under salt and drought stress, transgenic lines exhibited improved root elongation, increased shoot and root biomass, and higher relative water content compared to wild-type plants. Mechanistic investigations revealed that AcF3H overexpression led to reduced H₂O₂ accumulation and lower plasma membrane permeability under stress conditions, indicating enhanced antioxidative capacity and cellular membrane stability. These results suggest that AcF3H confers enhanced tolerance to abiotic stresses by promoting flavonoid-mediated ROS homeostasis. Our findings highlight AcF3H as a promising genetic target for engineering salt- and drought-tolerant crops. 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

Drought stress is a major constraint on alfalfa (Medicago sativa L.) production. Screening for drought tolerance at the seedling stage can accelerate the identification of resilient germplasm. In this study, six alfalfa cultivars were selected and subjected to drought stress at the seedling stage. Morphological traits (stem diameter, plant height, biomass, and root–shoot ratio) and oxidative/antioxidant indicators (malondialdehyde (MDA), superoxide (O₂•⁻), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX) activity) were quantified in leaves and roots. Drought stress significantly reduced plant height (by up to 42.4% in ZL2) and biomass (by up to 30% in some cultivars), but increased the root–shoot ratio (by 50–166%). MDA and O₂•⁻ levels increased by 10–174% in leaves and 8–65% in roots across cultivars. Antioxidant enzyme activities rose markedly: SOD by 23–125% in leaves and 2–100% in roots; POD by 47–240% (leaves) and 38–166% (roots); CAT by 9–129% (leaves) and 30–227% (roots); GR by 35–107% (leaves) and 23–172% (roots); APX by 8–175% (leaves) and 3–89% (roots), indicating a coordinated leaf–root antioxidant defense. Transcriptome analysis of the tolerant cultivar ZM3 revealed 853 differentially expressed genes, which were enriched in pathways such as the non-homologous end-joining DNA repair pathway. Multivariate assessment of seedling-stage performance identified ZM3 and ZL2 as the most drought-tolerant cultivars. Collectively, these findings provide germplasm leads and empirical evidence for coordinated leaf–root antioxidant strategies in alfalfa, informing the selection and improvement of drought-tolerant cultivars. Full article

Chickpea (Cicer arietinum L.) is a major annual legume crop with a balanced nutritional profile and a broad spectrum of bioactive constituents; these characteristics have made it a useful ingredient in health-oriented food applications. Chickpea supplies protein that is readily absorbed and digested, along with isoflavones and other bioactive plant compounds that act on physiological pathways associated with chronic disease prevention. Nonetheless, the combined pressures of drought, heat, cold, and salinity persistently limit its yield potential and cultivation stability. This review integrates the most recent progress in chickpea research, with emphasis on its intrinsic value derived from macronutrients, micronutrients, and bioactive metabolites. It further synthesizes the physiological determinants and metabolic reprogramming mechanisms underlying abiotic stress tolerance, outlines precision breeding strategies for developing resilient and high-quality ideotypes, and examines pathways for the high-value utilization of chickpea-derived processing by-products. Future efforts should focus on developing stress-resilient cultivars and expanding chickpea’s application in functional food innovation. Full article

Drought stress is the most pervasive abiotic constraint on global crop productivity, with projected intensification under climate change threatening the yields of staple crops including wheat, rice, maize, and legumes. Conventional breeding approaches have delivered limited gains against drought tolerance, constrained by the polygenic and multifactorial nature of stress adaptation, the complexity of genotype-by-environment interactions, and the inadequacy of field-based phenotyping under variable stress conditions. Omics technologies, including genomics, transcriptomics, proteomics, metabolomics, epigenomics, and phenomics, have substantially advanced the molecular dissection of drought tolerance by enabling high-resolution characterization of stress-responsive genes, regulatory networks, adaptive proteins, and metabolic reprogramming pathways. Specific traits targeted include root system architecture and depth, osmotic adjustment capacity through proline and glycine betaine accumulation, antioxidant defense mechanisms, ABA-mediated stomatal regulation, LEA protein accumulation, epigenetic stress memory, and yield stability under water deficit. This review systematically examines omics-based strategies for drought stress mitigation across major crops, highlighting individual omics contributions, multi-omics integration frameworks, computational tools including machine learning and AI-driven predictive modelling, and translational breeding applications. Case studies in wheat, rice, maize, and legumes illustrate how omics-driven approaches accelerate precision breeding for drought resilience through marker-assisted selection, genomic selection, and CRISPR-based gene editing. Challenges including data integration complexity, high implementation costs, limited cross-species transferability, and the need for field-scale validation of microbiome-based strategies are critically addressed. Future perspectives encompassing single-cell and spatial omics, AI-driven predictive breeding, digital agriculture integration, and international data governance frameworks are discussed. By aligning with climate-smart agriculture principles, multi-omics approaches provide a robust and transformative foundation for developing drought-resilient crop cultivars suitable for water-limited production systems worldwide. Full article

Chrysanthemum is one of the world’s four main cut flowers. However, postharvest drought stress severely disrupts water homeostasis, triggering reactive oxygen species burst and membrane lipid peroxidation, thereby reducing its ornamental quality and vase life. Melatonin serves as a multifunctional antioxidant and stress regulator. This study demonstrated that 200 μmol L⁻¹ melatonin effectively alleviated drought-induced leaf wilting, maintained relative water content, decreased the accumulation of MDA, H₂O₂, and O₂^•−, and enhanced the activities of SOD, CAT, POD, and APX. Concurrently, non-enzymatic antioxidants (proline, GSH, ASA) accumulated to high levels. RNA-seq analysis revealed that drought affects pathways closely related to the production of antioxidant and osmoprotectant metabolites, while melatonin initiated extensive transcriptional reprogramming and responded to drought stress through distinct pathways at the early (12 h) and late (24 h) treatment stages. Melatonin also modulated key transcription factor families, including bHLH, NAC, ERF, MYB, and bZIP. Collectively, exogenous MT mitigates drought damage in chrysanthemum cut flowers by coordinating antioxidant systems and complex transcriptional regulatory networks. This study provides a theoretical foundation for improving postharvest drought tolerance and prolonging the vase life of cut flowers. Full article