Selenium Supplementation Alleviates Drought-induced Impacts in Plants: A Global Meta-Analysis

Climate change has increased drought frequency and severity, impairing global plant growth and agricultural yield. To clarify selenium's (Se) potential in alleviating drought stress, we conducted a meta-analysis of 111 peer-reviewed studies covering 48 plant species, evaluating the associations between Se application and performance under water-limited conditions. Se supplementation was associated with a significant mitigation of biomass losses, with observed increases in shoot, root, and grain biomass of 21.2, 23.4, and 21.7%, respectively, and a 7.9% reduction in the root-to-shoot ratio. Efficacy varied with Se form, dose, and method; notably, Se(IV), concentrations ≥50 mg L^-1, and root application were linked to the largest gains. Se treatment was also correlated with improved plant water status, photosynthetic capacity, and nutrient uptake, while reducing oxidative stress markers and enhancing osmoprotectant accumulation. These findings demonstrate that Se application effectively enhances drought tolerance, providing targeted insights for crop management in water-stressed environments.