Selenium nanoparticles and nanocomposites in sustainable agriculture: Synthesis, stress alleviation mechanisms, and soil health impacts

Selenium nanoparticles (SeNPs) and selenium-based nanocomposite (SeNCs) have emerged as a promising tool in modern agriculture, due to their distinct physicochemical characteristics and potent biological activities. This review examines their synthesis, characterization, potential applications in enhancing agricultural productivity, with a focus on their biostimulant, antioxidant, and stress-alleviating properties. SeNPs contribute to improved plant growth and seed germination by modulating plant hormone signalling pathways such as auxin, gibberellin, and abscisic acid. Their ability to improve growth and stress resilience has been demonstrated by molecular docking studies, which show their strong and stable interactions with these hormones. Additionally, SeNPs enhance plant defense mechanisms against biotic and abiotic stresses by activating antioxidant systems, thereby reducing oxidative damage from pathogenic sources and environmental factors. Chitosan- based SeNCs, exhibit high biocompatibility and effectively reduce soil toxicity while maintaining essential soil microbial enzyme activities. The review highlights the significant potential of SeNPs and SeNCs to advance sustainable agriculture by enhancing crop performance, stress tolerance, and soil quality. These findings underscore the broader relevance of selenium nanotechnology in addressing global food security challenges and promoting environmentally responsible farming practices. • SeNPs and SeNCs enhance plant growth and stress tolerance. • SeNCs reduce soil toxicity while preserving key microbial enzyme activity. • SeNPs and SeNCs improve yields, nutrient uptake, and ecological safety.