Physiological and biochemical changes by nitric oxide and brassinosteroid in tomato (Lycopersicon esculentum Mill.) under drought stress

Drought stress produces many physiological and biochemical changes in plant affecting its life cycle and production. Oxidative damage and antioxidant defense responses are two components of plant to survive under drought stress. Nitric oxide (sodium nitroprusside, SNP) and brassinosteroid (24-epibrassinolide, EBL) were used in this experiment as single and combined application as foliar spray to study the mitigating effect of drought stress in two tomato genotypes EC-625652 (drought susceptible) and EC-620419 (drought tolerant). Drought stress produced harmful effect on number of leaves plant^?1, RWCL, fruit set percent, days to first fruit set, number of cluster plant^?1, lycopene content, fruit diameter and fruit yield. Plant produces reactive oxygen species (ROS), such as H₂O₂ in response to drought stress. Exogenous application of SNP and EBL, both in single and combined application, mitigated the deleterious effects of drought and improved drought tolerance by increasing SOD activity, fruit yield, and other physiological processes.