ROS Regulation by Salicylic Acid Under Abiotic Stress

First response of plants under abiotic stress is production of various kinds of reactive oxygen species (ROS). In order to adapt abiotic stress condition, morphological, metabolic, and genetic changes inside plants are necessary. Abiotic stress induced oxidative stress in plants either through increasing the defense responses (i.e. antioxidants) or causes the programs cell death (PCD) mainly under the influence of various factor. Salicylic acid (SA) is a potent phytohormone that plays a role in producing excessive ROS (pro-oxidant) as well as enhancing the activity of ROS scavenging enzymes (antioxidants) under stress condition. Interestingly, in time and concentration dependence manner, SA contributes to either increasing ROS production (pro-oxidant) or scavenging ROS (antioxidant) in plants. This pro-oxidant and antioxidants ratio are crucial in determining the survival or death of the plants under abiotic stresses. Initially, SA causes the increase in the production of ROS, especially H 2 O 2 species which are the crucial indicator to set up the antioxidant defense system that further helps the plants to ameliorate the abiotic stress. Thus, SA plays an essential role in amelioration of abiotic stress-induced ROS generation in plants.