Silicon oxide nanoparticles boost rice resilience to salinity by enhancing antioxidant defenses and stress regulation

Salinity stress is one of the most detrimental abiotic factors affecting plant development, harming vast swaths of agricultural land worldwide. Silicon is one element that is obviously crucial for the production and health of plants. With the advent of nanotechnology in agricultural sciences, the application of silicon oxide nanoparticles (SiO-NPs) presents a viable strategy to enhance sustainable crop production. The aim of this study was to assess the beneficial effects of SiO-NPs on the morpho-physio-biochemical parameters of rice (Oryza sativa L., variety: DRR Dhan 73) under both normal and saline conditions. To create salt stress during transplanting, 50 mM NaCl was injected through the soil. 200 mM SiO-NPs were sprayed on the leaves 25 days after sowing (DAS). It was evident that salt stress significantly hindered rice growth because of the reductions in shot length (41 %), root length (38 %), shot fresh mass (40 %), root fresh mass (47 %), shoot dry mass (48 %), and root dry mass (39 %), when compared to controls. Together with this growth inhibition, elevated oxidative stress markers including a 78 % increase in malondialdehyde (MDA) and a 67 % increase in hydrogen peroxide (H₂O₂) indicating enhanced lipid peroxidation were noted. Increasing the chlorophyll content (14 %), photosynthetic rate (11 %), protein levels, total free amino acids (TFAA; 13 %), and total soluble sugars (TSS; 11 %), all help to boost nitrogen (N; 16 %), phosphorous (P; 14 %), potassium (K; 12 %), and vital nutrients. The adverse effects of salt stress were significantly reduced by exogenous application of SiO-NPs. Additionally; SiO-NPs dramatically raised the activity of important antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT), improving the plant's ability to scavenge reactive oxygen species (ROS) and thereby lowering oxidative damage brought on by salt. This study highlights SiO-NPs' potential to develop sustainable farming practices and provides significant new insights into how they enhance plant resilience to salinity, particularly in salt-affected regions worldwide.