Alleviation of Drought Stress Effects in Two Rice (Oryza sativa L.) Cultivars by Foliar Application of Salicylic Acid

This study evaluated the alleviating effect of salicylic acid (SA) in two rice (Oryza sativa L.) cultivars differing in their tolerance to drought in the presence of PEG 6000-induced osmotic stress of 8 and 16%. The results revealed that foliar application with 0.25 mM SA considerably improved the growth parameters in DT and DS cultivars grown under drought. Concurrent with enhanced drought tolerance, the SA treatment showed a substantial increase in antioxidant enzyme activity and metabolite accumulation. Furthermore, PEG 6000-induced drought significantly upsurged the accumulation of hydrogen peroxide and hydroxyl radicals and enhanced the levels of protein carbonyl content. Interestingly, the SA foliar application also markedly declined ROS and protein carbonyl content under drought-stress conditions. These results indicated that the foliar application of salicylic acid proved to be effective in further boosting drought tolerance in DT and DS rice cultivars by overcoming the oxidative effects of drought stress.