Changes in Certain Antioxidative Enzymes and Growth Parameters as Affected by Complete Submergence and Subsequent withdrawal in rice Cultivars that Differ in Submergence Tolerance

Abstract

An experiment was conducted on the three Indica rice (Oryza sativa L.) cultivars IR 42, CR 383-10, and FR 13A, which are susceptible to submergence, submergence-avoiding, and tolerant to submergence, respectively. A deleterious effect of submergence was noted as both above-ground dry matter accumulation and chlorophyll content decreased during submergence and subsequent re-aeration. However, the rate of reduction was lower in the tolerant cultivar. The tolerant cultivar FR 13A maintained higher dry weight during submergence and subsequent re-aeration and accumulated lower proline and malondialdehyde contents than the other cultivars. The activities of the enzymes catalase, peroxidase, and superoxide dismutase, expressed on a per g fresh weight of leaves basis, were higher in FR 13A than in the other cultivars, both underwater and 24h after the initiation of re-aeration. However, ascorbic acid oxidase activity was lower in FR 13A. The cultivar CR 383-10, which has the capacity to accumulate more above-ground dry matter under normal conditions, showed a greater elongation ability under submergence and was similar to the susceptible cultivar IR 42 in terms of enzyme activities and the other parameters investigated during submergence and subsequent re-aeration.