Effect of high temperature on hydrogen peroxide scavenging enzymes during reproductive phase in aromatic rice cultivars

The inductive response of H₂O₂ scavenging enzymes was studied in leaves of aromatic rice when the plants were exposed to elevated temperature 55 days after transplanting (DAT). High temperature stress preferentially enhanced the activities of ascorbate peroxidase (APX) and non specific peroxidase (POX). Catalase (CAT) activity decreased with continuous exposure to heat stress although it was higher than control upto 15 days of stress (DAS) treatment. Thereafter, plants under normal temperature showed increased catalase activity as they experienced the stressful condition generated by shift towards reproductive stage. Hence our results suggest that (a) peroxidase enzymes detoxify H₂O₂ under high temperature (b) catalase enzyme scavenges H₂O₂ when the plant shifts from vegetative to reproductive stage.