Chapter 20 - Role of phytohormones as master regulators during the abiotic stress

Abstract

Plants’ intervention to abiotic stress is vast and immensely depends upon stress severity, plants’ developmental stages, and exposure duration of stress. The plant has its defensive mechanism to mitigate stress by altering morphological, physiological, and biochemical responses. Among all the stress-defensive factors, phytohormones have governed and induced as a signaling mediator that regulated plant’s adaptive responses to different stresses. Auxin, gibberellins, and cytokinin are multifunctional phytohormones in governing plant stress acclimatization. The role of abscisic acid and ethylene are considered to be the most potential regulators for abiotic stress signaling and tolerance. Emerging roles of endogenous chemical substances other than phytohormones in association with classical plant hormones cannot be subsided. They include brassinosteroid, jasmonic acid, and strigolactone in plant stress defense mechanisms and modulation of physiological responses. An increasing apparent on hormonal interaction in mitigating abiotic stress is to maintain their balance levels. Therefore a clear understanding of individual hormones’ regulatory action and their hormonal interaction in a responsive mechanism to changing environment will pave the way for the plants in improving stress adaptation and also productivity and quality.