Chapter 24 - Abiotic Stress-Induced Oxidative Stress in Rice

Abstract

Rice suffers greater damage when oxidative stress is induced by the prevailing environmental constraints. Oxidative stress results in the enhanced production of reactive oxygen species (ROS) including superoxide radical, hydrogen peroxide, and singlet oxygen. ROS are highly reactive in nature and react with important cellular molecules such as proteins, lipids, nucleic acid, and pigments and hence, cause irreparable damage to them. However, plants contain oxidative defense system in the form of enzymatic and non-enzymatic antioxidants that effectively scavenge ROS to limit the degree of damage due to oxidative stress. Plants undergoing oxidative stress usually stimulate their antioxidant defense system which in turn protects them from oxidative damage. Oxidative stress is measured in the form of accumulation of malondialdehyde and ROS. Malondialdehyde is the by-product of lipid peroxidation and the increase in the cellular levels of malondialdehyde is a good indicator of membrane integrity. Oxidative stress reduces growth, disturbs chloroplast ultrastructure, decreases chlorophyll, photosynthesis, relative water content and nutrient balance in rice. This chapter provides information on how abiotic stress-induced oxidative stress disturbs growth and development through inhibition of key physio-biochemical and molecular processes in rice. We have also discussed the possible underlying mechanisms that mediate plant defense responses under oxidative stress.