Comparison of Antioxidant System and Anaerobic Metabolism in Seedlings of Contrasting Maize Genotypes under Short Term Waterlogging

Aim: The aim of the study was to understand the biochemical mechanism of tolerance against waterlogging stress in two contrasting maize genotypes viz. Parkash (waterlogging tolerant) and Paras (waterlogging sensitive).

Methodology: Both the genotypes were subjected to short term waterlogging stress treatment (18 h) after fifteen days of germination. Two major biochemical defense systems under hypoxia conditions, namely antioxidant and anaerobic metabolism, were compared in leaf and root tissues of tolerant and sensitive maize genotypes.

Results: Both the genotypes efficiently mitigate the oxidative stress generated due to waterlogging, as shown by increased activities of SOD (superoxide dismutase), POX (peroxidase), CAT (catalase) and APX (ascorbate peroxidase) and constant level of H2O2 (hydrogen peroxide) and MDA (malondialdehyde) in plant tissues. ADH activity was also significantly enhanced in the roots of both the genotypes but ALDH activity was significantly induced in tolerant genotype only, whereas activity remained unchanged in sensitive genotype.

Conclusion: The present results suggest that under sudden short term waterlogging shocks, plant survival depends upon the simultaneous activation of ADH and ALDH activity for continuous energy supply and removal of toxic end products of anaerobic respiration.