Salicylic‐Acid Mediated Physiological and Molecular Mechanisms in Plants Under Drought Stress

Salicylic acid (SA) is considered as a signaling molecule in plants, and plays an important role in abiotic stress signaling. Several studies have been done to identify the protective role of the application of SA exogenously under drought stress. Studies showed that the ameliorating effect of SA is not always clear concerning the drought tolerance of plants. The exogenous application of SA regulates several aspects of growth, influences several physiologic processes, and induces changes at the molecular level. The major role of SA-induced tolerance to drought is related to regulation of transcription factors and expression of many drought-related genes. The impact of exogenous SA application depends on several factors such as the developmental stage and plant species, the level of drought stress, and the SA concentration and its endogenous level in the studied plant. This chapter explores the differential role of SA in mediating both the physiological and molecular mechanisms in plants under drought stress conditions.