Cerium Oxide Nanoparticles Decrease Drought-Induced Oxidative Damage in Sorghum Leading to Higher Photosynthesis and Grain Yield

Drought s a major abiotic stress affecting crop growth and yield worldwide. Drought induced oxidative stress results in the reduction of plant photosynthesis and reproductive success. Cerium oxide nanoparticles (nanoceria) possess potent antioxidant properties that can alleviate drought- nduced oxidative stress by catalytic scavenging reactive oxygen species (ROS), thereby protecting sorghum [Sorghum bicolor (L) Moench] photosynthesis and grain yield. Drought was imposed at the booting stage by withholding water for 21 d. Foliar-sprayed nanoceria (10 mg L-1) efficiently reduced leaf superoxide radical (41%) and hydrogen peroxide (36%) levels and decreased cell membrane lipid peroxidation (37%) under drought. Nanoceria increased leaf carbon assimilation rates (38%), pollen germination (31%), and seed yield per plant (31%) in drought-stressed plants relative to water-sprayed controls. Translocation study indicated that nanoceria can move from root to shoot of sorghum plants. Toxicity assays in mammalian cells *ndicated that nanoceria effective concentration (EC)(50) of >250 mg L-1 is well above the concentration used n this study. Foliar-sprayed nanoceria protect sorghum plants from oxidative damage under drought stress leading to higher grain yield.