Search Results (1,152)

Agriculture faces increasing challenges in ensuring food security under a changing climate, where abiotic stresses such as salinity and drought represent major constraints to crop productivity. These stresses induce complex physiological and biochemical alterations in plants, including osmotic imbalance, oxidative damage, and disruption of metabolic pathways, ultimately impairing growth and yield. In this context, the application of biostimulants has emerged as a sustainable strategy to enhance plant resilience. While synthetic products are widely available, growing attention is being directed toward natural bio-based products, particularly those derived from renewable biomasses and organic wastes, in line with circular economy principles. This review critically examines the current literature on bio-based products with biostimulant properties, with particular emphasis on vermicompost-derived extracts, humic-like substances, and macro- and microalgae extracts, focusing on their role in mitigating salt and drought stress in plants. The reviewed studies consistently demonstrate that these bio-products enhance plant tolerance to abiotic stress by modulating key physiological and biochemical processes, including hormonal regulation, activation of antioxidant defence systems, accumulation of osmoprotectants, and regulation of secondary metabolism. Moreover, evidence indicates that these bio-based inputs can improve nutrient use efficiency, photosynthetic performance, and overall plant growth under stress conditions. Overall, this review highlights the potential of non-microbial bio-based biostimulants as effective and sustainable tools for climate-resilient agriculture, while also underlining the need for further research to standardize formulations, clarify mechanisms of action, and validate their performance under field conditions. Full article

Signaling mediated by CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) peptides and their receptors is essential for plants to adapt to abiotic stress. To address the global issue of drought-induced growth inhibition and mortality in poplar (Populus spp.), this study investigated the function of the PtrCLE1A gene from Populus trichocarpa Torr. et Gray in drought tolerance regulation. We employed gene cloning, expression vector construction, and genetic transformation of poplar, combined with bioinformatics analysis, subcellular localization, phenotypic observation, physiological index measurement, and gene expression analysis. The results demonstrated that both PtrCLE1A and PtrCLE1B encode pre-propeptides containing a signal peptide, with an identical mature peptide sequence (RLSPGGPDPRHH), and their putative receptors are PtrCLV1/2. Furthermore, the PtrCLE1A pre-propeptide was localized around the plasma membrane in tobacco (Nicotiana benthamiana Domin) mesophyll cells, consistent with its predicted function. PtrCLE1A and PtrCLE1B are primarily expressed in the roots and xylem of P. trichocarpa. Additionally, only the PtrCLE1A promoter contained drought-responsive cis-elements, and its expression was induced by drought stress in root, xylem, and leaf tissues of P. trichocarpa. Overexpression of the PtrCLE1A gene in Populus tomentosa Carrière (triploid) significantly increased adventitious root length under osmotic stress. Overexpression lines exhibited 22.00% to 22.92% longer adventitious roots than EV lines at 50/100 mM mannitol, and 65.12% to 73.17% longer at 150 mM mannitol. The OE lines also exhibited higher photosynthetic capacity and instantaneous water use efficiency (iWUE), along with reduced membrane damage under drought conditions, indicating enhanced drought resistance. This study provides new genetic resources and a theoretical foundation for molecular breeding of drought-tolerant poplar. Full article

Cassava is one of the most important crops in global food security. It is the second most important staple crop in Africa. Its significance is enhanced by the fact that it very well tolerates droughts, and therefore it may be a prospective response to climate change in hot and dry areas. The potentials of cassava are under-utilized in Eastern Africa, and there is a lack of research studies regarding climate impacts on cassava yields in this region. The present research focuses on cassava production in Eastern Africa, analyzing the relationship of cassava yields, harvested areas, temperature, and precipitation from 1961 to 2023. The statistical analysis applies panel regression for the 63 years of time series, for the 15 most important cassava producing countries of Eastern Africa. Findings show that while the impacts of rainfall are insignificant on yields, the effects of temperature are significantly positive, indicating yield and area increases with warming climate. An expansion of the cassava growing area and the expanding rural population contributed to decreasing yields, probably because of the expansion of smallholder subsistence farming, suffering from to limitations in other farming resources. Therefore, even if climate change may benefit cassava production, other factors create severe limitations on improving yields. However, the positive response of the crop to rising temperatures is a clear sign that it is a useful choice for food security under climate change and would deserve more support from agricultural policymakers in Eastern Africa. Full article

Graphene oxide (GO) is a carbon-based nanomaterial explored for agricultural and forestry uses, but plant responses are strongly subject to both the dose and the route of exposure. We summarized recent studies with defined graphene oxide (GO) exposures by seed priming, foliar delivery, and root or soil exposure, while comparing annual crops with woody forest plants. Mechanistic progress points to a shared physicochemical basis: surface oxygen groups and sheet geometry reshape water and ion microenvironments at the soil–seed and soil–rhizosphere interfaces, and many reported shifts in antioxidant enzymes and hormone pathways likely represent downstream stress responses. In crops, low-to-moderate doses most consistently improve germination, root architecture, and tolerance to salinity or drought stress, whereas high doses or prolonged root exposure can cause root surface coating, oxidative injury, and photosynthetic inhibition. In forest plants, evidence remains limited and often relies on seedlings or tissue culture. For forest plants with long life cycles, processes such as soil persistence, aging, and multi-seasonal carry-over become key factors, especially in nurseries and restoration substrates. The available data indicate predominant root retention with generally limited root-to-shoot translocation, so residues in edible and medicinal organs remain insufficiently quantified under realistic-use patterns. This review provides a scenario-based framework for crop- and forestry-specific safe-dose windows and proposes standardized endpoints for long-term fate and ecological risk assessment. Full article

Drought events intensified by climate change severely compromise the physiological stability and productivity of Coffea arabica, particularly in rainfed systems, underscoring the need to identify cultivars with greater functional resilience. This study evaluated the physiological, nutritional and biochemical responses of seedlings from ten cultivars subjected to adequate irrigation (AW), severe water deficit (SWD) and rehydration (RI). Water potential, gas exchange, oxidative stress markers, stomatal traits and foliar macro- and micronutrients were quantified. Most cultivars exhibited pronounced reductions in the pre-dawn leaf water potential (Ψ_pd), photosynthesis (A), stomatal conductance (g_s) and transpiration (E), together with increases in oxidative stress indicators under SWD. In contrast, Obatá amarillo, Castillo, and Arará maintained greater hydraulic stability, more efficient stomatal regulation, higher water-use efficiency, and lower oxidative stress, accompanied by a more effective post-stress recovery after RI. Regarding nutrient dynamics, Geisha, Castillo, and Arará showed higher K⁺ accumulation, while Catimor bolo presented elevated Ca²⁺, P, and Fe²⁺ contents, elements associated with metabolic reactivation and structural recovery after stress. Geisha and Marsellesa displayed an adaptive, recovery-driven resilience strategy following drought stress. Overall, the findings identify Obatá amarillo, Castillo, and Arará as the most drought-tolerant cultivars, highlighting their potential relevance for breeding programs aimed at improving drought resilience in coffee. Full article

Drought can alter plant nutrient constraints, yet it remains uncertain whether macronutrient limitation hierarchies primarily reflect intrinsic responses or can be reshaped by targeted treatments. In a pot experiment with maize (Zea mays L.), we tested elemental sulfur (ES) and salicylic acid (SA) applied either as foliar sprays or soil amendments under two soil water regimes (30% vs. 60% field water capacity, FWC). Six treatments were evaluated (control, ES-foliar, SA-foliar, SA-soil, ES-soil, and ES + SA-soil; n = 72). Regression tree analysis of data indicated sulfur-potassium co-dominance under drought (24.6% importance each; R² = 0.914), while untreated controls showed nitrogen dominance (27.1%), confirming the S-K pattern is treatment-mediated. Under optimal irrigation (FWC 60%), nutrient importance was balanced across treatments (N, P, K, S; ~22–23%; R² = 0.991). ES + SA applied to soil produced the greatest drought tolerance, increasing dry biomass by 56% at FWC 30%, whereas ES-soil maintained favorable N/S ratios (9.64–9.86). Redundancy analysis confirmed that water availability explained 63.4% of nutrient variance and revealed significant Treatment × FWC interactions. These findings reveal that nutrient hierarchies can be strategically manipulated through targeted fertilization, representing a nutrient management approach for enhancing drought tolerance. Full article

It is generally believed that plant polyploids exhibit greater tolerance to abiotic stress conditions than their diploid counterparts. The aim of the present research was to investigate the mechanisms underlying enhanced drought tolerance in the autotetraploid apple ‘Redchief’ as compared to its diploid counterpart. The study was conducted on potted plants over two growing seasons, and simulated drought conditions were induced by limiting or withholding irrigation. Under drought stress, the responses of the clone ‘Redchief’ 4x-25 and its diploid counterpart were compared at physiological, biochemical, and molecular levels. In addition, changes in leaf anatomical structure, stomatal characteristics, and parameters related to growth dynamics were examined in drought-challenged plants. The results indicate that apple tetraploids have a greater ability to adapt to water-deficit conditions than diploids. Under drought stress, apple tetraploids exhibited better physiological and biochemical parameters and maintained a greater capacity for continued growth than diploids. We propose that the primary mechanism underlying the increased drought tolerance in apple tetraploids is a faster and more efficient activation of antioxidant defenses and proline accumulation compared to diploids. The high plasticity of anatomical traits in apple tetraploids in response to adverse environmental conditions was also demonstrated. Full article

Drought stress is one of the major constraints limiting crop productivity, primarily through oxidative damage, pigment degradation, and metabolic imbalance. Nanostructured selenium particles (SeNPs) have recently attracted attention for their potential to enhance plant tolerance to abiotic stress. In this study, green-synthesized SeNPs, with a main hydrodynamic size distribution in the range of 90–100 nm, were foliar applied to broccoli (Brassica oleracea var. italica) plants grown under well-watered (100% water holding capacity) and drought (50% water holding capacity) conditions at concentrations of 0, 10, 20 and 50 ppm. Drought stress significantly decreased chlorophyll a and b, total chlorophyll, and carotenoids, while increasing malondialdehyde (MDA) and proline levels, confirming oxidative stress and membrane damage. SeNPs treatments partially mitigated these effects by enhancing pigment stability, increasing carotenoid content, and reducing both MDA and proline accumulation. Phenolic and flavonoid responses exhibited a dose-dependent pattern with the highest stimulation at 50 ppm under drought and moderate enhancement at 10 ppm under optimal irrigation. Antioxidant capacity assays demonstrated that SeNPs modulate plant redox metabolism, in a context-dependent manner, particularly under water deficit. Peroxidase (POD) activity was also significantly induced under drought stress, mainly at 20 ppm. These results indicate that foliar-applied SeNPs can influence physiological and biochemical responses associated with drought tolerance in broccoli. The observed effects are consistent with nanoparticle–leaf surface interactions contributing to redox regulation and stress adaptation, rather than implying direct nanoparticle internalization. Full article

Drought stress is a major constraint on crop productivity in the Mediterranean region. Brassica crops are particularly valued in this region for their adaptability, nutritional benefits, and economic importance in sustainable farming systems. However, their productivity is highly sensitive to water deficits, necessitating the identification of drought-resilient genotypes. This study investigated the responses of five wild Brassica cretica populations and a commercial Brassica oleracea cultivar to a 50% reduction in irrigation, evaluating key physiological traits, leaf nutrient composition, and antioxidant activity. The experiment was conducted in the greenhouse facilities of the Laboratory of Vegetable Production, Agricultural University of Athens. The results revealed significant variation in drought tolerance among the tested populations. Specifically, an ecotype of B. cretica subsp. cretica (C: Akrokorinthos) and B. cretica subsp. laconica (E) showed substantial reductions in biomass, leaf area, and leaf number, whereas B. cretica subsp. aegaea (A: Manikia and B: Ymittos) and another ecotype of B. cretica subsp. cretica (D: Lasithi) maintained stable growth under water-limited conditions. Water deficit also significantly impacted leaf mineral composition, increasing NO₃⁻ and Na⁺ levels while decreasing P, Zn, and Mn. Additionally, drought stress enhanced antioxidant capacity and secondary metabolite production, as indicated by elevated ferric reducing antioxidant power, Trolox equivalent antioxidant capacity, total phenolic content, and total flavonoid content. Notably, the two studied populations of B. cretica subsp. aegaea (A: Manikia, B: Ymittos) and the population of B. cretica subsp. cretica from Lasithi (Crete) (D) exhibit promising drought tolerance, suggesting their potential for cultivation or breeding in water-limited environments. This research contributes to the broader effort of identifying favorable traits in crop wild relatives and to utilize these valuable genetic resources to develop climate-resilient crops for Mediterranean agriculture, where sustainable water use is critical for food security. Full article

Salt stress causes harm to plants through multiple aspects, such as osmotic pressure, ion poisoning, nutrient imbalance, and oxidative damage. Zinc finger proteins harboring two B-box domains, known as double B-box (DBB) proteins, constitute the DBB family. While DBB genes have been implicated in regulating circadian rhythms and stress responses in various plant species, their functions in cotton remain largely unexplored. The present study characterized the DBB gene family across the genomes of Gossypium hirsutum L., Gossypium raimondii L., and Gossypium arboreum L., revealing a complement of 58 members. These DBB genes were assigned to three separate clades based on phylogenetic analysis. Members possessing close phylogenetic relationships have similar conserved protein motifs and gene structures. All DBB proteins were predicted to be nuclear-localized, consistent with their roles as transcription factors. Furthermore, the presence of multiple cis-acting elements related to light, hormone, and stress responses in the promoters implies that GhDBBs are integral to cotton’s environmental stress adaptation. Expression pattern analysis indicated that the expression of GhDBB genes was associated with the plant’s response to multiple abiotic stresses, such as salt, drought, heat (37 °C), and cold (4 °C). The reliability of the expression data was confirmed by qPCR analysis of eight selected GhDBBs. Under 200 mM NaCl, Arabidopsis plants overexpressing GhDBB22 displayed longer roots and healthier true leaves than the wild-type controls. Conversely, VIGS-mediated silencing of GhDBB22 in G. hirsutum led to significantly reduced salt tolerance, accompanied by exacerbated oxidative damage. Taken together, the findings from our integrated genomic and functional analyses provide a foundational understanding of the molecular mechanisms through which proteins encoded by DBB genes are involved in the plant’s response to salt stress. Full article

Clinacanthus nutans (Burm.f.) Lindau is a medicinal plant known for its antioxidant, anti–inflammatory, and antiviral properties. Drought is a major abiotic stress affecting plant physiology and secondary metabolite biosynthesis. This study investigated the physiological and biochemical responses of C. nutans under drought stress. Relative water content declined with prolonged drought, while hydrogen peroxide and proline levels increased, indicating oxidative and osmotic stress. Antioxidant activities (DPPH and ABTS) peaked at days 4–8 and showed positive correlations with phenolic and flavonoid contents and triterpenoids, particularly schaftoside and lupeol. Molecular docking supported the bioactivity of drought–induced metabolites, with schaftoside and lupeol showing favorable interactions with inflammation–related targets. Multivariate analysis revealed that short–term drought enhanced stress tolerance and secondary metabolite accumulation, whereas prolonged stress reduced biosynthetic capacity and survival. These findings suggest that controlled drought exposure can enhance bioactive compound levels in C. nutans, supporting its potential for drought–adaptive cultivation for medicinal use. Full article

Aims: The plant and soil microbiome serve as a reservoir of beneficial endophytic bacteria, including plant-growth-promoting (PGP) Bacillus subtilis, which enhances nutrient acquisition and protects plants against environmental stresses. We isolated novel bacteria from cultivated peanut plants selected from agricultural fields that survived a season of water scarcity and high temperatures. Experiments were conducted to determine whether plant survival was partially attributable to the presence of beneficial microbes that could be harnessed for future biotechnology applications. Methods and Results: Seven bacterial isolates of Bacillus spp. were identified through 16S rRNA sequencing, revealing close affiliations to B. subtilis, B. safensis, and B. velezensis. Growth curve analysis and colony morphology characterization revealed distinct growth patterns across different media types, while phytohormone production assays demonstrated variable indole-3-acetic acid (IAA) synthesis among isolates. When applied as seed biopriming agents to two hybrid peanut varieties, bacterial inoculation significantly enhanced root surface area and root tip development, with B. subtilis-TAM84A showing the most pronounced effects on ‘Schubert’ roots. In addition, vegetative growth assessments indicated increased branch numbers and plant height, particularly with treatments with B. velezensis strains TAM6B and TAM61A, and a consortium of all isolates. Under drought conditions, inoculated plants exhibited delayed wilting and improved recovery after rehydration, indicating enhanced drought resilience. Conclusions: Several local Bacillus strains recovered from drought-tolerant peanut plants showed improved growth and drought tolerance in greenhouse-grown peanut plants. Ongoing field studies aim to evaluate the potential of regionally adapted microbial populations as soil amendments during planting. Impact Statement: This study demonstrates that local strains of Bacillus isolated from drought-resistant peanut plants possess significant potential as bioinoculants to improve growth and drought tolerance in potted peanut plants. This work provides a foundation for utilizing regionally adapted microbial populations to address agricultural challenges related to water scarcity. Full article

Drought stress substantially impairs citrus growth and alters the rhizosphere microbial composition; however, the role of these microbial communities in plant drought tolerance remains poorly understood. This study investigated the rhizosphere microbial structure, soil enzymatic activities, and physicochemical properties of drought-tolerant (DR) and drought-sensitive (DS) citrus varieties under drought stress conditions. High-throughput sequencing revealed that drought significantly altered microbial community composition, reducing the bacterial Shannon diversity by about 15% and enriching Gram-negative, stress-tolerant, and potentially pathogenic bacteria, as well as plant pathogenic fungi (upregulated 25.4% in DS), while reducing undefined saprotrophs (downregulated from 76.2 to 54.0% in DS). Notably, the DR variety exhibited a more stable and complex bacterial network, with 23.5% more edges and a higher proportion of positive correlations (54.3%), higher enrichment of beneficial fungi like Penicillium and Trichoderma, and unique recruitment of mycorrhizal fungi (up to 10.2%), which were nearly absent in DS. Furthermore, soil catalase and urease activities decreased under drought stress conditions. In contrast, acid phosphatase activity increased by up to 40% in DR. Correlation analyses indicated that these microbial shifts were closely associated with changes in soil nutrient availability. Our findings demonstrated that the drought-tolerant citrus variety modulates its rhizosphere microbiome towards a more cooperative and resilient state, highlighting the critical role of host-specific microbial recruitment in enhancing plant adaptation to drought stress for sustainable agriculture. Full article

Glycyrrhiza glabra L. is an economically significant plant that naturally grows in arid regions and is widely used in the cosmetics, food, and pharmaceutical industries. Its roots are the economically important part. However, it has weak drought tolerance during the seedling stage, and water scarcity has become a major limiting factor for improving the yield and quality of cultivated licorice. Therefore, this study conducted a pot experiment in which melatonin was applied via root irrigation to examine its effects on alleviating drought stress in G. glabra seedlings and on enhancing the yield and quality of its valuable parts. The results showed that under drought conditions, applying 100 μM melatonin yielded the most significant improvements in both yield and quality. Specifically, melatonin treatment increased root biomass by 138.10% and significantly boosted the levels of key bioactive compounds, including glycyrrhizic acid, liquiritin, glabridin, liquiritigenin, and isoliquiritigenin by 60.51%, 72.08%, 182.03%, 83.86%,and 30.68%, respectively. This study uniquely combined the Mantel test and random forest modeling for a comprehensive analysis of the experimental data. The analysis indicated that these effects were attributable to exogenous melatonin, which markedly enhanced antioxidant enzyme activities in G. glabra seedlings and reduced membrane lipid peroxidation products, thereby strengthening their antioxidant defense capabilities. Additionally, melatonin promoted the accumulation of osmotic adjustment substances and effectively improved photosynthetic performance. Our research provides a scientific basis for increasing both the quality and yield of G. glabra under drought conditions. Full article

Cortaderia selloana is an invasive grass spreading rapidly and becoming a serious environmental concern in many areas of the world. The species expanded to the Iberian Peninsula, including its eastern coast, where it increasingly occupies diverse ecosystems. This is the first evaluation of C. selloana’s tolerance to salinity and water deficit, combined with heat stress, during two key developmental stages: germination and early vegetative growth. Experimental trials were conducted using seeds and juvenile plants from two populations. Elevated temperature reduced germination, biomass accumulation, and shoot elongation, particularly when combined with water or salt stress. Drought exerted the strongest inhibitory effect on photosynthetic pigments, whereas salinity mainly affected carotenoid content, mostly in one of the populations analysed. Proline accumulation increased under drought and salinity, reaching up to 70 µmol·g⁻¹ DW, but to a lesser extent when combined with a heat treatment, suggesting enhanced proline catabolism at high temperature. Total soluble sugars tended to increase under water deficit (from ~75 to >100 mg equivalent of glucose g⁻¹ DW), indicating a potential osmoprotective shift from proline to carbohydrates. These results highlight intraspecific variability in stress tolerance and emphasise that C. selloana’s success in Mediterranean environments depends on its capacity to withstand transient but not prolonged combined stresses. Full article