Variable Effects of Silicon on Salt Tolerant Indices in Rice Genotypes at Seedling Stage

Silicon (Si) is known to improve salt tolerance in rice. However, the correlation of silicon with different physiological and biochemical indices of salt tolerance is not properly understood. Two rice genotypes with different silicon accumulation ability were evaluated along with two standard checks in response to 10 dS/m salinity stress (NaCl) and external Si source (1mM) during their seedling stage. All evaluated genotypes showed an evident decrease in biomass and chlorophyll content under salinity stress, while reporting an enhances in Si accumulation, Na+/K+ ratio, proline, electrolyte leakage, lipid peroxidation, hydrogen peroxide, and antioxidant activities. The external Si supplementation significantly improved rice tolerance to salinity through increased Si content, low Na+/K+ ratio, better osmolyte production, reduced membrane permeability, and improved antioxidant enzyme activities. Multivariate factor analysis with principal component factor statistically correlates and visualizes silicon accumulation with salt tolerance indices. The Hierarchical clustering in rice obtained based on the study of salt tolerance indices, distinguishes genotypes with different treatments into three clusters. In conclusion, the clustering grouped salt-tolerant Var.Lunishree and salt stress high silicon accumulating Var.Swarna together validates silicon mitigating effect on salinity in rice.