The Contribution of Phytohormones in Plant Thermotolerance

Plants, mostly being sessile, have to face the adversity of nature with scant chance of escape. The unpredictable or abrupt changes in the environment limit plant productivity to a considerable extent. A plant's abiotic constraint offers more devastating effect as compared to their biotic counterparts. High temperature (HT) stress negatively impacts various physiological and biochemical features associated with growth and development and also determine reproductive success. Plants judiciously respond to these changes and somehow manage to resist or tolerate a certain extent by various means, such as induction of stress-related proteins, osmolytes, and antioxidant systems, thus minimizing the stress-induced discomfort. The phytohormones (primarily key player of plant growth and development) were found modulated under HT conditions and their exogenous application provide considerable tolerance. Moreover, the biosynthesis and signaling mutants of some of them were also inefficient in the HT management. Considering their wide acceptance in the amelioration of HT, the present chapter has been structured to cover the major phytohormone HT protectants, which will facilitate further understanding of plants' HT management strategies.