Ambient ozone pollution degrades rice grain nutritional quality and straw feed value under field conditions in Bangladesh.

Poor nutrient retention in agricultural soils limits crop productivity and fertilizer use efficiency. Enhancing the soil capacity to retain cations such as Ca2⁺, Mg2⁺, and K⁺ is critical for sustaining plant nutrition, yet strategies that simultaneously improve cation availability and crop performance remain underexplored. This study investigated a pyrolysis temperature dependent biochar strategy to improve nutrient retention and plant performance by integrating urea with biochar produced at 300, 500, and 700°C. The effects of urea alone (UA) and biochar produced at 300, 500, and 700°C, blended with urea (BB300, BB500, BB700), and impregnated with urea (IB300, IB500, IB700), were evaluated in a soil-plant system of water spinach. Among all treatments, IB500 was the most effective, significantly improving key soil properties, including cation exchange capacity (CEC), and the availability of Ca2⁺, Mg2⁺, and K⁺, while increasing microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN). These soil improvements promoted substantial enhancements in root system architecture; IB500 resulted in a 56% increase in root length, an 81% increase in surface area, and a 91% increase in root tip formation compared to urea alone. The robust root system facilitated more vigorous shoot development, including a 33% increase in leaf number, a 59% increase in leaf area index, and a 44% increase in chlorophyll content. Physiologically, IB500 treated plants exhibited a 12% higher photosynthetic rate, a 13% increase in stomatal conductance, and a 79% increase in nitrogen uptake. Biochar pyrolyzed at 500°C and impregnated with urea showed strong potential as a multifunctional soil amendment, enhancing nutrient retention, soil fertility, and plant physiological performance. These findings identify pyrolysis temperature as a key regulator of biochar, soil, and nutrient interactions, offering a mechanistic and sustainable strategy to improve crop productivity through rhizosphere optimization.

Nano-biochar regulates soil enzymatic activities and nitric oxide signaling to improve photosynthesis and nutrient balance in Brassica napus under salt stress: Implications for precision agriculture.

High levels of copper (Cu) in agricultural soils, resulting from intensive input use, negatively affect crop growth and physiology. This study evaluated whether the beneficial microorganisms Trichoderma harzianum and Bacillus subtilis can mitigate Cu toxicity in Canavalia ensiformis. The experiment followed a completely randomized design in a 5 × 3 factorial scheme, with five Cu doses (0, 50, 150, 250, and 350 mg kg−1) and three microbial treatments (inoculation with T. harzianum, B. subtilis, or a non-inoculated control), totaling 75 experimental units. Cu reduced plant growth and physiological performance; however, microbial inoculation mitigated these effects. B. subtilis was more effective at lower Cu doses, increasing shoot length by up to 24% and root fresh biomass by 65% compared with the control, while maintaining higher photosynthetic rates and stomatal conductance under Cu stress. In contrast, T. harzianum performed better at higher Cu doses, increasing root dry biomass by more than twofold (112%; p < 0.05) and enhancing Cu accumulation in shoots and roots. It also improved plant water use efficiency under higher metal stress. Under controlled conditions, C. ensiformis tolerated Cu levels up to 250 mg kg−1. The effectiveness of microbial inoculation was dose-dependent, with B. subtilis performing better at lower Cu concentrations and T. harzianum at higher levels. These findings highlight the potential of microbial inoculation as a sustainable strategy to enhance phytoremediation of Cu-contaminated soils.

Broccoli (Brassica oleracea var. italica) is considered an important vegetable crop valued for its high nutritional profile. The quality and Productivity of broccoli both are affected by heavy metal contamination, particularly cadmium (Cd). The current investigation focused on the potential role of silicon (Si) in alleviating Cd-induced stress in broccoli plants. A pot experiment was conducted under a completely randomized design with three Cd levels (0, 0.5, and 1 mM) and three Si concentrations (0, 1, and 2 mM). Morphological, physiological and anatomical traits were evaluated to assess plant responses to Cd stress and Si supplementation. Gas exchange traits, including photosynthetic rate, transpiration and stomatal conductance were estimated using an infrared gas analyzer (IRGA). Stress induced by Cd significantly reduced plant growth and physiological performance, whereas exogenous Si application notably improved plant tolerance. Application of Si improved photosynthetic activity (up to 3.24 μmol m−2s−1), plant height (44 cm), root length (20.63 cm) and shoot biomass compared with Cd-stressed plants without Si application. Additionally, Si application increased both fresh and dry biomass, indicating improved growth under Cd stress. Anatomical observations further revealed that Si supplementation mitigated Cd-induced cellular damage by maintaining better cellular organization and larger cell areas in root, stem, and leaf tissues, including the epidermis, cortex, phloem, and xylem. Overall, the results demonstrate that silicon plays a significant role in enhancing Cd stress tolerance in broccoli by improving morpho-physiological performance and cellular integrity. These findings suggest that Si supplementation could serve as an environmentally friendly strategy to reduce Cd toxicity and support sustainable crop production in contaminated soils.

The valorization of anaerobic digestates through slow pyrolysis offers a sustainable pathway for agricultural systems. This study assessed the effects of digestate type (swine, cattle, and dairy) and pyrolysis temperature (400, 500, and 600°C) on biochar properties and evaluated their impact on maize (Zea mays) fodder grown under hydroponic-like soilless conditions. Thirty-six treatments were evaluated in a factorial design combining digestate source, temperature, and application rate (0-6.25g per container). Biochar from dairy digestate (BDST) pyrolyzed at 500°C exhibited the most favorable characteristics, with high carbon content (60.4%), low electrical conductivity (≈ 916 µS cm-1), and improved water and nutrient retention. At an application rate of 6.25g per container, BDST-500 also achieved the highest SPAD and dry mass values. In contrast, swine- and cattle-derived biochars presented higher ash and salinity, reducing their agronomic performance. Multivariate analysis indicated that digestate type was the main determinant of plant physiological performance, beyond the individual effects of pyrolysis temperature and application rate. Overall, dairy-derived biochar demonstrates strong potential as a functional amendment for hydroponic fodder systems and as a tool to advance circular bioeconomy practices.

Synergistic effects of carbon dots and arbuscular mycorrhizal fungi on mitigating PFAS stress and reinforcing the purification performance of constructed wetlands.

The efficiency of foliar fertilizers is crucial for sugarcane as it can enhance nutrient utilization and reduce environmental impacts, particularly within the context of more sustainable agriculture. This study evaluated the effects of four foliar fertilizers (FH+ Vigor, Vitale Nitro, Tardus N, and N Top) on the photosynthetic parameters and productivity of sugarcane. A randomized block design was used, with five blocks and a control treatment. Increases were observed in parameters such as transpiration, stomatal conductance, and internal CO₂ concentration, particularly with FH+ Vigor and Vitale Nitro. However, these improvements did not translate into greater biomass or raw material quality. Despite the lack of impact on productivity, the study highlights that the proper selection and management of foliar fertilizers can optimize plant physiological performance under specific conditions. These results emphasize the importance of tailored strategies to maximize fertilizer efficiency.

Continuous cultivation in solar greenhouses degrades black soil, leading to soil-borne diseases, nutrient imbalances, reduced porosity, and microbial dysbiosis, all of which collectively decrease crop productivity. Improving soil structure and microbial balance often requires costly amendments that are inconsistent in their effectiveness. This study evaluated two low-cost soil amendments—carbonized rice hull (CRH) and fermented rice hull (FRH)—using colored pepper as a model crop. Treatments included soil mixed with 30% CRH (T1), 30% FRH (T2), and untreated black soil (CK). Both amendments significantly improved soil physical properties. Compared with CK, soil porosity increased by 8.80% in T1 and 17.84% in T2, while water-holding capacity increased by 75.32% and 133.45%, respectively. Soil microbial richness, as indicated by Abundance-based Coverage Estimator (ACE) and Chao indices, followed the order T2 &gt; T1 &gt; CK. Plant physiological performance was also enhanced. Net photosynthetic rate increased by 7.18% (T1) and 15.33% (T2), plant height increased by 14.42% (T1) and 28.85% (T2), and root activity improved significantly. Fruit weight increased by 15.33% in T1 and 21.62% in T2. Both rice hull amendments improved soil quality and promoted crop growth, with FRH performing consistently better. These findings indicate that fermented rice hull is a promising, low-cost strategy for greenhouse soil remediation.

Calcareous soils, characterized by high pH and low nutrient availability, pose significant challenges to sustainable sugar beet production. Combining organic soil amendments with advanced nano-fertilizers may offer a synergistic strategy to enhance crop productivity and quality in such marginal environments. A 2-year field study (2022/2023 and 2023/2024) was conducted using a split-plot design to evaluate the effects of three compost rates (0, 3, and 6 tons acre−1) and five foliar nano-micronutrient combinations (control, Fe + Mn, Fe + B, Mn + B, Fe + Mn+B applied at 100 mg L−1 each). Growth, physiological, yield, and technological quality parameters of sugar beet were analyzed. The integrated application of 6 tons compost acre−1 and the nano Fe + Mn+B mixture resulted in powerful synergistic effects, consistently outperforming all other treatments. This optimal combination maximized photosynthetic pigments (e.g., increased chlorophyll a by 27%), boosted antioxidant enzyme activities (catalase by 29%, peroxidase by 42%), and enhanced growth parameters, leading to a 55% greater leaf area index. Consequently, it achieved the highest sucrose content (up to 19.85%), extracted sugar percentage (17.25%), root yield (27.12 tons acre−1), and sugar yield (4.68 tons acre−1), representing yield increases of 28–32% and 63–69%, respectively, over the compost-only control. For optimal sugar beet productivity in calcareous soils, an integrated management approach is recommended, consisting of soil amendment with 6 tons of compost per acre supplemented by foliar application of a combined nano-iron, manganese, and boron mixture. This strategy effectively enhances soil health, plant physiological performance, and ultimately, sugar yield and quality, providing a sustainable pathway for cultivation in nutrient-deficient calcareous environments.

Alkaline stress is considered as one of the major abiotic stress factors limiting plant production on a global scale. This study was conducted in vitro to evaluate the physiological, morphological, and biochemical responses of Garnem rootstock to NaHCO3-induced alkaline stress using sodium nitroprusside (SNP) and salicylic acid (SA) treatments. The aim was to alleviate the negative effects of alkaline stress. The study was conducted during the rooting stage of Garnem rootstock plantlets obtained through in vitro micropropagation. SNP and SA (50, 100, and 150 µM) were applied in vitro to counteract alkaline stress induced by NaHCO3 (0 mM, 20 mM, and 40 mM) at various concentrations. As the severity of alkaline stress increased, damage occurred to morphological, physiological, and biochemical parameters. The SNP and SA treatments alleviated the harmful effects of alkaline stress. In the study, the highest survival rate was observed with 0 mM NaHCO3 + 50 µM SA (98.33%) and 50 µM SNP (95.00%), while the lowest survival rate was observed with 40 mM NaHCO3 + 150 µM SA (6.67%). The longest shoots were observed with 0 mM NaHCO3 + 100 µM SNP (4.25 cm), and the shortest shoots were observed with 40 mM NaHCO3 + 150 µM SA (0.77 cm). The highest number of leaves was found with 20 mM NaHCO3 + 50 µM SA (20.63 per plantlet), and the lowest number of leaves was found with 20 mM NaHCO3 + 150 µM SNP (5.33 per plantlet). The highest plant fresh weight was observed with the 0 mM NaHCO3 + 50 µM SNP (2.07 g), while the lowest plant fresh weight was observed with the 20 mM NaHCO3 + 150 µM SA (0.14 g) application. The highest plant dry weight was observed with the 0 mM NaHCO3 + 150 µM SA (0.24 g), while the lowest plant dry weight was observed with the 20 mM NaHCO3 + 150 µM SA and 40 mM NaHCO3 + 150 µM SA (0.04 g) applications. The highest injury was observed with 40 mM NaHCO3+ 50 µM SA, 40 mM NaHCO3+ 100 µM SA and 40 mM NaHCO3+ 150 µM SA (4.00) and the lowest injury was observed with 0 mM NaHCO3+50 µM SNP, 0 mM NaHCO3+100 µM SNP and 0 mM NaHCO3+150 µM SNP (1.00). Membrane permeability increased under high alkaline stress, while 100 µM SNP applications reduced this rate, contributing to the preservation of cellular structure. All SNP and 50 µM SA applications increased leaf relative water content in response to alkaline stress. Significant decreases in chlorophyll a, chlorophyll b, and total chlorophyll concentrations were observed under alkaline stress conditions. However, SNP treatments alleviated these negative effects and increased chlorophyll levels. Furthermore, SNP treatments significantly reduced hydrogen peroxide (H2O2) and malondialdehyde (MDA) accumulations. Overall, the results demonstrated that SNP treatments at all tested concentrations effectively mitigated NaHCO3-induced alkaline stress by improving morphological traits, maintaining membrane integrity, enhancing leaf relative water content and reducing oxidative damage in Garnem rootstock plantlets. In contrast, salicylic acid exhibited a concentration-dependent response, with low doses (50–100 µM) alleviating stress effects, whereas the high concentration (150 µM) induced phytotoxicity and markedly suppressed plant growth and physiological performance.

Management practices that optimize physiological responses of crops can be applied in agriculture to achieve higher productivity in challenging environments limited by nutrient availability. Extremely Low Frequency (ELF), a type of non-ionizing radiation in the range of 0.3 to 300 Hz, interacts with biological systems and has potential applications in sustainable agriculture. This study evaluates the effects of ELF on morphophysiological parameters of soybean plants during the vegetative stage. Plants grown under controlled conditions were subjected to ELF treatments—Control, TA (which increases interatomic spacing), and TB (which decreases interatomic spacing)—in combination with three nutrient solution strengths (50%, 75%, and 100% of the Hoagland solution). Chlorophyll index, root and shoot length, and dry mass were measured at the end of experiment. ELF treatment significantly enhanced chlorophyll index, with treatment TB showing the greatest increase. This may suggest improved nutrient assimilation of key nutrients such as nitrogen and magnesium, which are critical for chlorophyll synthesis. These findings demonstrate the potential of ELF treatment to enhance plant physiological performance, even under nutrient-limited conditions. When combined with nutrient solutions, ELF exposure may promote plant health and growth by increasing chlorophyll index and may improve nutrient uptake. This approach represents a promising and sustainable strategy to boost crop productivity and resource use efficiency in agricultural systems.

Wood vinegar (WV), a by-product of biomass pyrolysis rich in organic acids and phenolic compounds, has gained increasing attention as a sustainable input for crop production, mainly through foliar application. However, its high content of volatile organic compounds (VOCs) suggests that WV may (also) interact with plants through the gaseous phase, a pathway that has so far been overlooked. This study tested the hypothesis that WV can modulate plant physiological performance, metabolic status, and nutrient accumulation not only via direct foliar contact but also through exposure to WV-derived VOCs. Lettuce (Lactuca sativa L.) was used as a model crop and grown under controlled environmental conditions. Plants were subjected to weekly treatments consisting of either foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution in a sealed chamber, without direct contact between the liquid and plant tissues, and were compared with untreated controls. Notably, plants exposed exclusively to WV-derived VOCs showed responses similar to those observed following foliar application. Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zn. For both treatments, the efficiency of photosystem II remained stable, indicating the absence of photochemical stress, while stomatal conductance, transpiration rate, intercellular CO2 concentration, and net photosynthetic rate were markedly reduced, suggesting a regulated stomatal response. Physiological, biochemical, and mineral parameters were assessed using non-destructive optical techniques, gas exchange measurements, spectrophotometric assays, and X-ray fluorescence analysis. These findings indicate that exposure to the volatile fraction released from WV under the exposure conditions adopted in this study can elicit biostimulant-like responses comparable to those observed after foliar application.

Nano-biofertilizers represent a cutting-edge innovation at the convergence of nanotechnology and biological nutrient management, offering a sustainable and efficient alternative to conventional agrochemical fertilizers. These advanced formulations combine beneficial microorganisms such as nitrogen-fixing bacteria, phosphate-solubilizing microbes, and plant growth–promoting rhizobacteria with nanoscale nutrient carriers to enhance the precision, efficiency, and sustainability of crop nutrition. In contrast to traditional fertilizers, which often experience significant nutrient losses through leaching, volatilization, and runoff, nano-biofertilizers are designed to deliver nutrients in a controlled and targeted manner, thereby substantially improving nutrient use efficiency (NUE) and reducing environmental contamination. Recent research (2023–2025) highlights the effectiveness of nanocarrier systems derived from chitosan, alginate, silica, and biodegradable polymers in encapsulating nutrients and microbial inoculants. These systems protect bioactive components from adverse soil conditions and enable their gradual release in alignment with plant nutrient demand. Such controlled delivery enhances nutrient uptake while fostering a stable and biologically active rhizosphere. The synergistic interaction between nanoparticles and microbial consortia has been shown to improve plant physiological performance, including enhanced root development, increased chlorophyll content, elevated enzymatic activity, and greater tolerance to abiotic stresses such as drought, salinity, and nutrient deficiency. From a sustainability standpoint, nano-biofertilizers reduce dependence on synthetic fertilizers, lower greenhouse gas emissions, and mitigate nutrient pollution in terrestrial and aquatic ecosystems. Their application aligns with climate-smart and precision agriculture strategies by supporting site-specific and dose-efficient nutrient management. Although promising, challenges related to large-scale production, regulatory frameworks, long-term ecological impacts, and economic feasibility remain. Addressing these issues will be crucial for the widespread adoption of nano-biofertilizers as a transformative solution for sustainable agriculture and global food security.

Abiotic stresses are among the most significant constraints on global crop productivity, adversely affecting plant growth, physiological performance, and yield stability. Environmental stresses such as salinity, drought, heat, and low temperature disrupt cellular homeostasis by impairing photosynthesis, altering membrane integrity, and inducing excessive accumulation of reactive oxygen and nitrogen species (ROS and RNS). Elucidating the physiological, biochemical, and molecular mechanisms underlying plant responses to these stresses is critical for the development of stress-resilient crop varieties. This review synthesizes recent advances derived from both conventional and emerging approaches used to investigate plant abiotic stress tolerance. Classical methodologies, including physiological assays, functional genomics, and molecular marker-assisted selection, continue to provide essential insights into adaptive traits. In parallel, modern strategies such as transcriptomics, genome-wide association studies (GWAS), proteomics, and integrated multi-omics analyses have revealed complex regulatory networks, candidate genes, and metabolic pathways associated with stress adaptation. The integration of genomics, transcriptomics, proteomics, and metabolomics enables systems-level analysis of stress signaling, gene regulation, and metabolic reprogramming, offering a comprehensive understanding of plant adaptive responses. Collectively, this review highlights the importance of combining traditional approaches with advanced omics technologies to accelerate the development of climate-resilient crops and to guide crop-specific, scalable strategies for enhancing tolerance under rapidly changing climatic conditions.

Drought poses a major challenge for global agriculture, demanding strategies that improve crop resilience while safeguarding water and nutrient resources. Plant growth-promoting rhizobacteria (PGPR)-based biostimulants offer a sustainable approach to enhance resource-use efficiency under water-limited conditions. This study evaluated two commercial PGPR biostimulants applied to maize (Zea mays L.) and tomato (Solanum lycopersicum L.) seedlings grown under well-watered (80% field capacity) and water-stressed (40% field capacity) conditions. Both products improved plant growth and physiological performance, although responses were crop-specific. Inoculated tomato seedlings accumulated up to 35% more shoot biomass under optimal watering (1.6 g in non-inoculated seedlings compared with 2.5 g in inoculated seedlings), whereas maize maintained biomass production under drought, consistent with its higher intrinsic water-use efficiency, showing increases of approximately 50% (well-watered: 0.5 g versus 0.8 g; water-stressed: 0.3 g versus 0.7 g in non-inoculated and inoculated seedlings, respectively). Biostimulant application enhanced the acquisition and internal utilization of essential mineral resources, increasing leaf concentrations of (i) the macronutrients P (up to 300%), K (up to 70%), Mg (up to 220%), and Ca (up to 85%), and (ii) the micronutrients B (up to 400%), Fe (up to 260%), Mn (up to 240%), and Zn (up to 180%). Maximum nutrient increases were consistently observed in water-stressed maize seedlings inoculated with biostimulant 2. Antioxidant activities, particularly ascorbate peroxidase and catalase, increased by 20–40%, indicating more effective mitigation of oxidative stress. Principal component analysis revealed coordinated adjustments among growth, nutrient-use efficiency, and physiological traits in inoculated plants. Overall, PGPR-based biostimulants improved early drought tolerance and resource-use efficiency, supporting their potential as sustainable tools for climate-resilient agriculture. Field-scale studies remain necessary to confirm long-term agronomic benefits.

Abstract The expansion of white mustard ( Sinapis alba L.) cultivation onto low-fertility sandy soils necessitates to enhance oil productivity and establishing environmentally friendly soil relations as part of a sustainable development strategy. Combining organic soil amendments with natural biostimulants could offer an integrated solution by improving both the root zone environment and plant physiological performance. A two-year field study (2023/2024-2024/2025) employed a split-plot design to investigate the effects of plant compost (0, 5, 10, 15 tons per hectare) as a main plot and foliar biostimulants (seaweed extract at 2, 4 ml L −1 ; moringa leaf extract at 15, 30 %; active yeast at 6, 12 ml L −1 ) as sub-plots on white mustard grown under drip irrigation. All compost and biostimulant treatments significantly improved growth, yield, and biochemical parameters relative to the control. Compost rate at 15 t ha −1 yielded the highest values for vegetative growth (e.g., plant height, leaf area), yield components (pod number, seed yield), and fixed oil production. Among biostimulants, seaweed extract at 4 ml L −1 was most effective. A significant interaction was observed, with the combination of 15 t ha −1 compost and 4 ml L −1 seaweed extract producing the most pronounced results, increasing seed yield per hectare and oil yield by approximately 305 % and 875 %, respectively, compared to the untreated control. This treatment also maximized photosynthetic pigments and NPK content in plant tissue. The integrated application of 15 t ha −1 plant compost and 4 ml L −1 seaweed extract is a highly effective, sustainable cultivation strategy for maximizing growth, seed yield, and oil content of white mustard in sandy soils.

The agricultural industry faces increasing environmental degradation due to the intensive use of conventional chemical fertilizers, leading to water pollution and alterations in soil composition. In addition, root-knot and cyst nematodes are major constraints to cucumber production, causing severe root damage and yield losses worldwide, underscoring the need for sustainable alternatives to conventional fertilization and pest management. Under greenhouse conditions, a four-month cultivation trial evaluated vegetable oil-, micronutrient-, and activated flavonoid-based biostimulants, applying Key Eco Oil® (Miami, USA) via soil drench (every 15 days) combined with foliar sprays of CropBioLife® (Victoria, Australia) and KeyPlex 120® (Miami, USA) (every 7 days). Results showed reduced parasitic nematodes by 66% in soil and decreased gall formation by 41% in roots. Chlorophyll fluorescence and infrared gas analysis revealed higher oxygen-evolving complex efficiency (38%), increased PSII electron transport, improved the fluorescence decrease ratio, also known as the vitality index (Rfd), and higher CO2 assimilation compared to conventional treatments. Processed cucumbers showed higher sugar and nearly double ascorbic acid content, with improved flesh consistency and color. Therefore, the application of these bioactive products significantly reduced nematode infestation while enhancing plant growth and physiological performance, underscoring their potential as sustainable tools for crop cultivation and protection. These results provide evidence that sustainable bioactive biostimulants improve plant resilience, productivity, and nutritional quality, offering also an environmentally sound approach to pest management.

Drought stress is a major abiotic constraint limiting crop productivity and ecosystem stability in arid and semi-arid regions. The use of stress-adapted plant growth-promoting rhizobacteria (PGPR) represents a sustainable strategy to enhance crop resilience while maintaining soil ecological function. This study characterized a desert-adapted, halotolerant Exiguobacterium sp. C-20, isolated from the rhizosphere of Panicum antidotale in the Cholistan Desert (Pakistan), for its plant growth-promoting traits and its ability to mitigate drought stress under controlled conditions. The strain exhibited strong phosphate-solubilizing activity, produced indole-3-acetic acid (IAA), and generated ammonia in vitro, confirming its functional potential as a PGPR. In greenhouse experiments, seed and soil inoculation of maize (Zea mays L.) hybrids (G-3 and G-7) exposed to drought (40% field capacity) significantly improved photosynthetic performance, stomatal conductance, chlorophyll stability (SPAD values), biomass accumulation, and tissue moisture content compared with non-inoculated controls. These improvements reflect enhanced plant physiological performance under water deficit rather than speculative mechanisms. Overall, the findings identify Exiguobacterium sp. C-20 as a promising microbial resource for developing eco-sustainable bioinoculants to improve drought tolerance and productivity in dryland agroecosystems.

Salinity stress is a major abiotic constraint limiting pepper (Capsicum annuum L.) productivity by disrupting water relations, ionic balance, and metabolic processes. Silicon (Si), although not essential, has emerged as an effective stress mitigator in plants. This study evaluated the potential of exogenous silicon application to alleviate salinity-induced growth inhibition and yield losses in pepper. A pot experiment was conducted under controlled conditions using a Completely Randomized Design with five treatments comprising different silicon concentrations (0, 1, 2, and 3 mM) under salinity stress (6 dS m⁻¹), along with a non-saline control. Morphological, physiological, biochemical, ionic, and yield-related parameters were assessed. Salinity stress significantly reduced plant height, leaf area, chlorophyll content, relative water content, and yield, while increasing proline accumulation and Na⁺ concentration. Silicon application markedly improved plant growth and physiological performance under salinity. The highest Si dose (3 mM) resulted in maximum plant height, leaf area, chlorophyll retention, antioxidant enzyme activity, K⁺ accumulation, and fruit yield, while significantly reducing Na⁺ uptake and proline content. Enhanced antioxidant defense and improved ionic homeostasis contributed to better stress tolerance. Correlation analysis revealed strong positive associations among growth, physiological traits, antioxidant activity, and yield, while Na⁺ concentration showed a strong negative relationship with yield attributes. Overall, the findings demonstrate that silicon application effectively mitigates salinity stress by improving water relations, oxidative defense, and nutrient balance, leading to enhanced growth and yield of pepper under saline conditions.