Search Results (1,038)

Pre-sowing seed treatment (priming) is a strategic tool for programming future crop yield, aimed at improving early plant development and enhancing stress resilience. This study investigated the effects of priming wheat seeds with 100 µM ibuprofen on early ontogeny under optimal conditions and salt stress (100 mM NaCl). An evaluation of germination energy, growth parameters, phytohormone levels (abscisic acid, indolylacetic acid, and cytokinins) and the status of the antioxidant system in 7-day-old seedlings demonstrated that ibuprofen treatment stimulates wheat growth and tolerance, despite its absence of accumulation in plant tissues. Modulation of hormonal balance plays a key role in these protective effects: under optimal conditions, ibuprofen elevates abscisic acid and indolylacetic acid levels, while under salt stress, it prevents excessive abscisic acid accumulation and mitigates the stress-induced decline in indolylacetic acid and cytokinins. Furthermore, ibuprofen promotes a coordinated increase in glutathione, ascorbate, and H₂O₂ levels, concomitant with the activation of key enzymes (glutathione reductase and ascorbate peroxidase), thereby enhancing the plants’ antioxidant potential. Under saline conditions, ibuprofen pretreatment also reduces stress-induced dysregulation of this system. Therefore, ibuprofen acts as a hormetic preconditioning agent that improves seedling vigor and stress tolerance by fine-tuning hormonal signaling and redox metabolism. Full article

Low salinity tolerance during germination and early seedling establishment limits large-scale cultivation of halophytes for forage, food, restoration, and conservation purposes. This study evaluates the potential of redox priming to enhance salt tolerance in the perennial C₄ halophyte grass Urochondra setulosa, which could be used as a revegetation and phytoremediation crop for coastal saline lands. Fresh seeds were found to be non-dormant with ~90% mean final germination (MFG) in distilled water. Redox priming, including hydrogen peroxide (H₂O₂), melatonin (MT), sodium nitroprusside (SNP; a nitric oxide donor), and ascorbic acid (AsA), significantly accelerated the germination rate index (GRI) and reduced mean germination time (MGT) without altering MFG under non-saline conditions. Salinity severely suppressed germination, as unprimed seeds reached only ~1% MFG with ~99% germination reduction (GR) and near-zero germination stress tolerance index (GSTI) at 200 mM NaCl. All priming treatments significantly improved MFG, GRI, and GSTI and decreased GR, with H₂O₂ priming showing the highest amelioration. Ungerminated seeds from all treatments recovered ~90% germination capacity in water, indicating enforced dormancy owing to osmotic constraints. Salinity did not impair growth in unprimed seedlings. However, MT priming uniquely enhanced total length, leaf area, and seedling vigor index (SVI) at 200 mM NaCl, while MT and SNP priming resulted in the highest chlorophyll and carotenoid contents. Multivariate analyses confirmed MT’s consistent superiority across traits under stress. Thus, H₂O₂ priming optimizes germination, while MT priming improves seedling vigor and offers a practical, targeted strategy to improve early-stage salinity tolerance in U. setulosa for coastal revegetation and sustainable saline agriculture. Full article

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

This study investigates the effects of saline reclaimed water recharge on soil salt accumulation and water migration in Xinjiang, China, aiming to provide scientific guidance for the sustainable utilization of reclaimed water in arid regions. Indoor vertical infiltration simulation experiments were conducted using reclaimed water with varying salinity levels (0, 1, 2, 3, and 4 g L⁻¹) to evaluate their impacts on soil water–salt distribution and infiltration dynamics. Results showed that irrigation with saline reclaimed water increased soil pH and significantly enhanced both the infiltration rate and wetting front migration velocity, while causing only minor changes in the moisture content of the wetted zone. When the salinity was 2 g L⁻¹, the observed improvement effect was the most significant. Specifically, the cumulative infiltration increased by 22.73% after 180 min, and the time required for the wetting peak to reach the specified depth was shortened by 21.74%. At this salinity level, the soil’s effective water storage capacity reached 168.19 mm, with an average moisture content increase of just 6.20%. Soil salinity increased with the salinity of the irrigation water, and salts accumulated at the wetting front as water moved downward, resulting in a characteristic distribution pattern of desalination in the upper layer and salt accumulation in the lower layer. Notably, reclaimed water recharge reduced soil salinity in the 0–30 cm layer, with salinity in the 0–25 cm layer decreasing below the crop salt tolerance threshold. When the salinity of the reclaimed water was ≤2 g L⁻¹, the salt storage in the 0–30 cm layer was less than 7 kg ha⁻¹, achieving a desalination rate exceeding 60%. Reclaimed water with a salinity of 2 g L⁻¹ enhanced infiltration (wetting front depth increased by 27.78%) and desalination efficiency (>60%). These findings suggest it is well suited for urban greening and represents an optimal choice for the moderate reclamation of saline-alkali soils in arid environments. Overall, this study provide a reference for the water quality threshold and parameters of reclaimed water for urban greening, farmland irrigation, and saline land improvement. Full article

Heat shock transcription factors (HSFs) play a central role in mediating plant responses to abiotic stress. Anthocyanins, one of the most important secondary metabolites in plants, contribute to both stress tolerance and the enhancement in crop nutritional quality. However, the possible role of HSFs in regulating anthocyanin biosynthesis in sweet potato (Ipomoea batatas L.) remains unknown. This study conducted a genome-wide analysis of the sweet potato HSF gene family to explore their functions related to anthocyanin metabolism and salinity stress. Multiple stress-inducible promoter elements were identified within IbHSF22, including those induced by drought, salt, heat, ABA, and light. For functional characterization of this gene, a 35S-driven overexpression construct was prepared and then transformed into Nicotiana benthamiana. Overexpression of IbHSF22 led to a nearly two-fold increase in anthocyanin content, concurrently with the elevated expression of key structural genes such as NtCHS, NtF3H, NtDFR, and NtANS. Under salt stress, the transgenic plants also exhibited enhanced tolerance, which was associated with maintained antioxidant enzyme activity and concerted induction of stress-responsive genes, events that collectively resulted in decreased oxidative damage. Therefore, the present work identifies IbHSF22 as an integrator of anthocyanin biosynthesis and salt defense mechanisms. These findings provide a conceptual basis and candidate gene strategy for dual improvement in stress resilience and nutritional quality in sweet potato breeding. Full article

Salinity stress severely limits crop productivity worldwide. While plant growth-promoting rhizobacteria (PGPR) are known to alleviate abiotic stress, the specific mechanisms mediated by their volatile organic compounds (VOCs) remain largely elusive. In this study, an in vitro split-plate system was used to investigate the effects of VOCs emitted by Bacillus velezensis SQR9 on Arabidopsis thaliana seedlings under salt stress. Exposure to SQR9 VOCs significantly enhanced Arabidopsis salt tolerance, evidenced by increased biomass and root growth. Mechanistically, SQR9 VOCs mitigated salt-induced damage by increasing chlorophyll content, modulating osmolytes, and reducing malondialdehyde (MDA) levels. SQR9 VOCs alleviated oxidative stress by decreasing ROS (H₂O₂, O₂⁻) accumulation and enhancing antioxidant enzyme (SOD, CAT, POD) activities. Furthermore, SQR9 VOCs maintained ion homeostasis by significantly reducing leaf Na⁺ accumulation, maintaining a high K⁺/Na⁺ ratio, and upregulating key ion transporter genes. Analysis of the headspace from SQR9 cultured on MSgg medium identified 2,3-butanediol (2,3-BD) as a major active VOC. Exogenous application of 2,3-BD successfully mimicked the growth-promoting and salt-tolerance-enhancing effects of SQR9. Our findings demonstrate that SQR9 VOCs, particularly 2,3-BD, systemically prime Arabidopsis for salt tolerance by co-activating the antioxidant defense system and the SOS ion homeostasis pathway. Full article

Salt stress is one of the most harmful abiotic stresses that strongly affects plant growth and crop yield, limiting agricultural production across the Mediterranean area. Consequently, there is a growing need to identify resilient crops capable of adapting to saline conditions and enhancing desirable qualitative traits through a wide spectrum of physiological, biochemical, and molecular mechanisms. Therefore, this study aimed to investigate the effects of four different NaCl concentrations (0, 12.5, 25, and 50 mM) on the growth rates, biometric and productive characteristics, leaf gas exchange, and biochemical traits of Stevia rebaudiana Bertoni plants grown hydroponically (in a floating raft system) in a glasshouse. The results showed that NaCl-treated plants exhibited reduced growth parameters and productivity and a lower content of photosynthetic pigment content compared to the control. On the other hand, an increase in antioxidant capacity was observed due to the significant accumulation of total phenols and flavonoids, especially when stevia plants were treated with 50 mM NaCl. Similarly, the leaf concentration of ascorbic acid and glutathione remarkably increased. This provides new insight into the antioxidant defense strategy of S. rebaudiana under salt stress, demonstrating that stevia plants rely mainly on non-enzymatic mechanisms to counter oxidative stress. Although the highest salinity level (50 mM NaCl) resulted in the lowest content of steviol glycosides (stevioside + rebaudioside A), plants treated with 25 mM NaCl showed both the highest rebaudioside A content and Reb A/Stev ratio, which are desirable properties for the production of high-quality natural sweeteners. Overall, these findings underline that stevia can be considered a moderately salt-tolerant species, and mild stress conditions are able to promote the biosynthesis of interesting secondary metabolites, such as polyphenols and rebaudioside A. Full article

Circular RNAs (circRNAs) are covalently closed RNA molecules that regulate various biological processes in plants. However, the functions of most identified circRNAs remain unclear. Here, we report a nucleoplasmic-localized circRNA, Vv-circRCD1, derived from exons 2 and 3 of the grape VvRCD1 gene. Overexpression of Vv-circRCD1 significantly shortened primary root length and increased root hair number and length, notably, and improved the salt tolerance in Arabidopsis. Transient overexpression also significantly enhanced salt tolerance of grapevines. In silico analyses confirmed direct sequence complementarity between Vv-circRCD1 and the Vvi-miR399 family, and Vv-circRCD1 and Vvi-miR399 target genes (involved in salt stress responses) showed consistent expression patterns under salt stress, indicating a Vv-circRCD1–Vvi-miR399–target gene regulatory module may mediate salt tolerance. These results not only identified Vv-circRCD1 as a novel regulator of grapevine salt tolerance, but also highlighted its potential in improving crop stress resistance, providing a practical reference for crop breeding. Full article

Functional properties of coastal halophytes are important for development of salt-tolerant cash crop cultures. The study of salt tolerance in coastal dune-building grass Leymus arenarius holds significant importance for its application in land reclamation, soil stabilization, and enhancing crop resilience to salinity stress. We used two accessions (LA1 and LA2) of L. arenarius to compare effects of salinity caused by NaCl and NaNO₃ on growth, ion accumulation and mineral nutrition in controlled conditions. L. arenarius plants exhibited high tolerance to sodium salts, with distinct effects on growth and development observed between chloride and nitrate treatments. While both salts negatively impacted root biomass, nitrate treatment (50–100 mmol L⁻¹) increased leaf number and biomass in LA2 plants, whereas chloride treatment decreased tiller and leaf sheath biomass. Despite individual variations, salinity treatments showed comparable effects on traits like tiller and leaf count, as well as leaf blade and sheath biomass. Salinity increased water content in leaf blades, sheaths, and roots, with LA2 plants showing the most pronounced effects. Chlorophyll a fluorescence measurements indicated a positive impact of NaNO₃ treatment on photosynthesis at intermediate salt concentrations, but a decrease at high salinity, particularly in LA2 plants. The accumulation capacity for Na⁺ in nitrate-treated plants reached 30 and 20 g kg⁻¹ in leaves and roots, respectively. In contrast, the accumulation capacity in chloride-treated plants was significantly lower, approximately 10 g kg⁻¹, in both leaves and roots. Both treatments increased nitrogen, phosphorus, and manganese concentrations in leaves and roots, with varying effects on calcium, magnesium, iron, zinc, and copper concentrations depending on the type of salt and tissue. These findings highlight the potential of L. arenarius for restoring saline and nitrogen-contaminated environments and position it as a valuable model for advancing research on salt tolerance mechanisms to improve cereal crop resilience. Full article

Aromatic coconut (Cocos nucifera L.) is valued in the consumer market primarily for its distinctive fragrance, which is largely attributed to the compound 2-acetyl-1-pyrroline (2AP). The accumulation of 2AP has been observed in several crops, such as rice, when exposed to salt stress. In rice, exposure to salt stress influences the activity of enzymes, alters amino acid metabolism, and modulates the expression of genes associated with 2AP formation. Nevertheless, the processes responsible for 2AP biosynthesis in aromatic coconut under salt stress conditions are still not well clarified. In this study, five-month-old aromatic coconut seedlings were subjected to four distinct levels of sodium chloride (NaCl) treatment (0, 100, 200, and 300 mM). This experiment was conducted to investigate the mechanisms involved in salt-induced responses and the biosynthesis of 2AP in aromatic coconut. Although salt stress did not produce any apparent injury in the coconut seedlings, it led to a marked decline in chlorophyll content. Meanwhile, salt stress markedly enhanced the accumulation of betaine and boosted the activities of antioxidant enzymes such as superoxide dismutase and catalase. The aromatic coconut demonstrated a moderate level of salt tolerance. Salt stress also had a significant influence on 2AP biosynthesis. Under salt stress conditions, the 2AP content increased substantially, reaching its highest level with a 93.55% rise compared to the control. Furthermore, the synthesis of 2AP in aromatic coconut under salt stress appears to be primarily regulated through the metabolic pathways of proline and glutamate. Therefore, salt stress enhances 2AP production, with 200 mM NaCl identified as the optimal concentration for its accumulation. Full article

In arid regions, irrigation is essential for sustaining crop production, but irrigation water often contains high levels of salts that may reduce yields. This study aimed to evaluate crop responses to irrigation water with salinity levels exceeding 4 g/L (≈6.25 dS/m). A large-scale field survey was conducted across several Tunisian governorates, covering a wide range of crops and production systems. Irrigation water salinity and corresponding crop yields were recorded and analyzed to determine tolerance patterns under real farming conditions. Results indicate that, even under high salinity conditions, several cropssuch as carrot (Daucus carota), barley (Hordeum vulgare), and tomato (Solanum lycpersicum), can maintain high yields, highlighting their potential for saline irrigation in arid regions. These findings provide valuable insights for irrigation management, crop selection, and the development of sustainable agricultural practices in arid environments. Full article

Soil salinity is a major constraint on global crop production, disrupting photosynthesis, ion homeostasis, and growth. Beyond the roles of classic osmoprotectants and antioxidant enzymes, flavonoids have emerged as versatile mediators of salt stress tolerance at the interface of redox control, hormone signaling, and developmental plasticity. This review summarizes current evidence on how salinity remodels flavonoid biosynthesis, regulation, and function from cellular to whole-plant scales. We first outline the phenylpropanoid–flavonoid pathway, with emphasis on transcriptional control by MYB, bHLH, and NAC factors and their integration with ABA, JA, and auxin signaling. We then discussed how post-synthetic modifications such as glycosylation and methylation adjust flavonoid stability, compartmentation, and activity under salt stress. Functional sections highlight roles of flavonoids in ROS scavenging, Na⁺/K⁺ homeostasis, membrane integrity, and the modulation of ABA/MAPK/Ca²⁺ cascades and noncoding RNA networks. Spatial aspects, including root–shoot communication and rhizosphere microbiota recruitment, are also considered. Based on this synthesis, we propose a flavonoid-centered stress network (FCSN), in which specific flavonoids function as key nodes that connect metabolic flux with hormonal crosstalk and stress signaling pathways. We argue that reconceptualizing flavonoids as central stress network regulators, rather than generic antioxidants, provides a basis for metabolic engineering, bio-stimulant design, and breeding strategies aimed at improving crop performance on saline soils. Full article

Oats (Avena sativa L.) are a staple grain and forage crop with substantial market demand. In China, they are the second most-imported forage grass, only after alfalfa (Medicago sativa L.). Enhancing the salt tolerance of oats to facilitate their cultivation in saline areas can thereby increase forage yield and promote the utilization of saline land, which constitutes an important reserve land resource in China. This study aimed to identify the bacterial strain Bacillus sp. LrM2 (hereafter referred to as strain LrM2) to determine its precise species-level classification and evaluate its effects on oat photosynthesis and growth under salt stress through indoor pot experiments. The results indicated that strain LrM2, capable of urease production and citrate utilization, was identified as Bacillus mojavensis. The strain LrM2 had a positive effect on shoot and root growth of oats under 100 mM NaCl stress conditions. Strain LrM2 inoculation modulated osmotic stress in oats under 100 mM NaCl stress by significantly increasing soluble sugar and decreasing proline content in leaves. It inhibited Na⁺ uptake and promoted K⁺ absorption in the roots, thereby reducing Na⁺ translocation to the leaves and mitigating ionic toxicity. Inoculation with strain LrM2 significantly increased photosynthetic pigment content (chlorophyll a, carotenoids), improved gas exchange parameters (stomatal conductance, transpiration rate, net rate of photosynthesis), enhanced PSII photochemical efficiency (maximum quantum yield, coefficient of photochemical quenching, actual photosynthetic efficiency of PSII, electron transfer rate), and reduced the quantum yield of non-regulated energy dissipation. These improvements, coupled with increased relative water content and instantaneous water use efficiency, thereby collectively enhanced the overall photosynthetic performance. In conclusion, strain LrM2 represents a promising bio-resource for mitigating salt stress and promoting growth in oats, with direct applications for developing novel biofertilizers and sustainable agricultural strategies. Full article

Wheat is one of the most important crops contributing to global food and nutritional security. However, the gradual increase in soil salt content significantly impairs wheat growth and development, ultimately resulting in reduced yields. Therefore, enhancing the salt tolerance of wheat is of significant importance. Salt stress commonly induces oxidative stress in plants, and nucleoredoxin (NRX) has been shown to effectively maintain redox homeostasis under stress conditions. However, the functional role and molecular mechanism of the NRX gene in regulating salt tolerance in wheat remain to be elucidated. The results of this study demonstrated that TaNRX1-2D homologous overexpression (OE) lines exhibited significantly enhanced tolerance to salt stress. The survival rate and antioxidant enzyme activities (including superoxide dismutase and catalase) in the OE lines were higher than those in the wild type (WT). In contrast, the levels of superoxide anion (O₂⁻), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) in the OE lines were markedly lower than those in the WT. Conversely, the RNA interference (RNAi) lines displayed opposing trends. The results of yeast one-hybrid (Y1H) and dual luciferase assays (D-LUC) demonstrated that the TaERD15L-3B transcription factor positively regulated the expression of the TaNRX1-2D gene by binding to the ABRERATCAL cis-acting element in the TaNRX1-2D promoter. Through luciferase complementation assay (LCA), bimolecular fluorescence complementation (BiFC) assay, and a “mutation capture strategy”, it was found that TaNRX1-2D (C54, 327S) interacted with TaCAT2-B, indicating that TaCAT2-B was the target protein of TaNRX1-2D. The results of data-independent acquisition (DIA) proteomics analysis indicated that TaNRX1-2D may mediate salt tolerance in wheat through the positive regulation of nsLTP protein abundance and the negative regulation of hexokinase protein abundance. In general, the TaERD15L-3B/TaNRX1-2D regulatory module played a crucial role in conferring salt tolerance in wheat. This study provided an important theoretical basis and identified a potential gene target for developing salt-tolerant wheat varieties through molecular breeding approaches. Full article

Egyptian rice landraces represent a unique genetic reservoir shaped by arid environments, yet their genomic and transcriptional response to salt stress remains largely unexplored. Here, we integrated genomic, transcriptomic, and population genetic analyses to systematically unravel the mechanisms of salt tolerance in this vital germplasm. Resequencing 56 Egyptian accessions uncovered a treasure trove of genetic variation, including 18,204 novel SNPs. An expanded GWAS on 258 accessions discovered 17 novel loci for salt tolerance. Parallel RNA-Seq analysis of a salt-tolerant-susceptible pair (Giza 176 vs. 9311) under stress delineated a defense network centered on phenylpropanoid and lipid metabolic pathways in the tolerant genotype. The power of our integrated approach was exemplified by the convergent identification of ONAC063, where GWAS loci, transcriptional responsiveness, and haplotype-phenotype association collectively validated its role. Furthermore, selection sweep analysis highlighted 62 candidate genes under divergent selection. Our study not only positions Egyptian rice as a key resource for allele mining but also establishes a robust multi-omics pipeline for bridging genetic diversity with complex traits, accelerating the discovery of functional genes for breeding climate-resilient crops. Full article