ABSTRACT
Abiotic stresses, such as salinity, drought, low/high temperature, low/high light, mineral/oxygen deficiency, heavy metals, UV radiations, etc., are the various factors that disrupt normal plant growth, development and productivity. These stresses lead to the production of certain toxic molecules called reactive oxygen species (ROS), which include hydrogen peroxide (H2O2), superoxide radical (O2 •− ), hydroxyl radical (OH • ), etc. ROS are found in various cellular compartments that induce oxidative damage to lipids, proteins and nucleic acids. Plants have evolved several metabolic adaptations for their survival under stress. Of which, a prominent one is the balance between the production and detoxification of ROS, sustained by various enzymatic antioxidants (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase) and non-enzymatic antioxidants (ascorbic acid, glutathione, proline, α-tocopherol, carotenoids, phenolic acids, flavonoids, sugars, proline, etc.) that protect the cells from cytotoxic effects. Studies on various physiological and molecular mechanisms of abiotic stress have led to the characterization of a number of genes involved in antioxidation mechanism and associated signaling cascades. Moreover, various achievements have been made in developing transgenic plants with enhanced antioxidation potential. This chapter describes the oxidative stress and its management in plants during abiotic stress in plants. The recent developments in elucidating the roles of phytohormones in plants to enhance the antioxidation potential to counter abiotic stress conditions are also described.
