Multifaceted Roles of Salicylic Acid and Jasmonic Acid in Plants Against Abiotic Stresses

Plants are always facing different kinds of stresses. Among them abiotic stresses are major hazard to plant growth and development. Impaired physiological, biochemical, and molecular processes are the adverse effects that occur in plants in response to different abiotic stresses. The damaged metabolism and retarded growth of plants in abiotic stress conditions also affect the crop productivity worldwide. Different phytohormones have been proposed to take part in the abiotic stress tolerance in plants. Among them, salicylic acid (SA) is one of the most important one, which plays a crucial role in abiotic stress responses apart from its role in biotic stresses during pathogenesis. In response to abiotic stresses, endogenous level of SA is increased. So, proper application of SA before stress conditions can provide a mechanism of abiotic stress tolerances in plants. For that reason, SA can be used as a tool for combating different types of abiotic stresses in plants. However, the exact mechanism of SA signaling during abiotic stress conditions is still least understood, but it has been stated that SA performs its role in plants with the accumulation of H2O2. Some of the distinguishing factors are the key points in SA-mediated abiotic stress tolerance in plants, such as concentration of SA, mode of application, endogenous SA level, type of plant species, etc. Another important phytohormone jasmonic acid (JA) also has a role in abiotic stress conditions by changing the endogenous level. The exogenous application of JA can also induce the tolerances of plants during the abiotic stress conditions. In this chapter, we are trying to summarize different roles and modes of action of SA and JA in plants during the abiotic stress conditions.