Biogenic Chitosan-Selenium Nanoparticles for Improved Stress Resilience in Rice Seedlings

Abstract

Salt stress is a major limiting factor in global agricultural production, severely affecting rice yield and quality, particularly during the seedling stage. Nanoparticles (NPs), including green synthesized metallic-based Selenium nanoparticles (SeNPs) and organic-based chitosan nanoparticles (CTSNPs), have shown potential in mitigating salt stress. This study explored using Calotropis procera (Leaves extract) to biosynthesize SeNPs and CTSNPs, confirmed through UV-Vis's spectra at 350 nm and 300 nm, respectively, and FTIR analysis indicating stabilization.Dynamic light scattering (DLS), X-ray Diffraction (XRD), Scanning electron microscopy SEM with EDS confirmed their physical stability. Rice seedlings were grown hydroponically and subjected to 50, 100 and 150 mM NaCl stress at the 3-leaf stage (14 days after sowing) and morphological parameters were recorded to determine the most deleterious level. After 3 days of 150 mM Salt stress, SeNPs and CTSNPs (0, 6, 12, and 24 ppm) were applied to roots. SeNPs showed superior performance in improving root and shoot length, biomass, photosynthetic pigments, and antioxidant enzyme activity (SOD, POD, APX, CAT, and proline) compared to CTSNPs. The findings indicate that the root application of SeNPs and CTSNPs mitigates salinity stress by enhancing the antioxidant system. Future studies should investigate stress-related gene expression and conduct field trials to validate these findings under natural conditions.