Unravelling the Influence of Silicon Nanoparticles on Growth and Physiological Changes in Rice Under Cadmium Stress

ABSTRACT Cadmium (Cd) is a toxic trace metal that causes severe environmental pollution and alters plants' physiological and biochemical responses. Although commercially synthesised silicon nanoparticles (SiNP) have been reported in alleviating biotic and abiotic stresses, the role of PV (photovoltaic) driven SiNP in modulating plant physio‐biochemical response under Cd stress has not systematically evaluated to strengthen the circular economy framework. A glasshouse experiment was therefore conducted to investigate the effects of solar PV panel‐sourced SiNP on rice's physico‐chemical responses under Cd stress. Three SiNP concentrations (0, 0.5, and 1 mM) and three Cd levels (0, 10, and 20 µM) were used in this hydroponic culture. The results revealed that increases in Cd stress significantly reduced the photosynthetic pigment content, plant growth and biomass. Elevated Cd levels also enhanced the accumulation of hydrogen peroxide (H 2 O 2 ), electrolyte leakage (EL) and lipid peroxidation (MDA), suppressed antioxidant activity in roots and shoots, which caused severe damage to the roots and leaves. In contrast, SiNP supplementation (0.5 and 1 mM) improved photosynthetic pigments, antioxidant activity, cell membrane stability and overall growth under 20 µM Cd stress. Both SiNP levels significantly downregulated the H 2 O 2 , EL and MDA content, thereby minimzing leaf tissue injury under 10 and 20 µM Cd stress. Transmission electron microscopy (TEM) observations confirmed that SiNP supplement substantially alleviated Cd‐induced ultrastructural damage in leaf cells. The study concluded that PV‐derived SiNP application mitigated oxidative stress, promoted rice growth and biomass, improved Cd stress tolerance, and offered a promising strategy for sustainable farming practices in Cd‐prone areas.