Effect of Cerium Oxide Nanoparticles on Rice: A Study Involving the Antioxidant Defense System and In Vivo Fluorescence Imaging

Previous studies have reported the uptake of cerium oxide nanopartides (nCeO(2)) by plants, but their physiological impacts are not Ye t well understood. This research was aimed to study the impact of nCeO(2) on the oxidative stress and antioxidant defense system in germinating rice seeds. The seeds were germinated for 10 days in nCeO(2) suspension at 62.5 125 250 d 500 mg L-1 concentrations. The Ce uptake, growth performance, stress le anvels, membrane damage, and antioxidant responses in seedlings were analyzed. Ce in tissues increased with increased nCeO(2) concentrations, but the seedlings showed no visible signs of toxicity. Biochemical assays and in vivo imaging of H2O2 revealed that, relative to the control, the 62.5 and 125 mg nCeO(2) L-1 treatments significantly reduced the H2O2 generation in both shoots and roots. Enhanced electrolyte leakage and lipid peroiddation were found in the shoots of seedlings grown at 500 mg nCeO(2) L-1 Altered enzyme activities and levels of ascnrbate and free thiols resulting in enhanced membrane damage and photosynthetic stress in the shoots were observed at 500 mg nCeO(2) L-1. These findings demonstrate a nCeO(2) concentration-dependent modification of oxidative stress and antioxidant defense system in rice seedlings