Remodeling of Anti-oxidant Systems, Chlorophyll Contents, and Productivity in Peanut Genotypes under Waterlogging Stress

Many crops are affected by heavy rains and subsequent periods of waterlogging during the maturity phase. Therefore, waterlogging effect on antioxidative enzyme activity, chlorophyll content, lipid peroxidation, and grain yield were investigated using two contrasting genotypes of peanut: the waterlogging-tolerant line, DH-86, and the waterlogging-sensitive line, TAG-24, to better understand the biochemical and physiological mechanisms of waterlogging tolerance. Under the greenhouse environment, potted peanut plants were waterlogged up to 60 days after sowing. The activities of the antioxidant enzyme were measured by comparing the superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (POD) activities between waterlogging-tolerant and waterlogging-sensitive genotypes of peanut. The early stimulation of their anti-oxidant systems was responsible for variation in tolerance levels between the two genotypes. The increased, superoxide dismutase (SOD) and catalase (CAT) activities played a significant role in DH-86 in maintaining productivity and growth to recover from waterlogging stress. The susceptibility of TAG-24 was associated with lipid peroxidation damage, a reduction in chlorophyll concentration, and antioxidant enzyme activity. The photosynthate accumulation in the stems and leaves was caused by an imbalance of the source-sink relationship, and this is the principal reason for yield loss under waterlogging. TAG-24 reduced more grain yield than DH-86, most likely because more photosynthate was accumulated in the stem and leaves of TAG-24 and could not be transported to the pod efficiently. According to these findings, the better protection of DH-86 from waterlogging-induced oxidative damage is because of the maintenance of the enhanced antioxidant enzyme activity and induced grain yield capacity.