Physiological studies on salt tolerance in rice IV. Effect of salinity on superoxide dismutase and catalase activities
1990
Wang Zongli | Li Jiankun | Wang Zhixia (Jiangsu Provincial Academy of Agricultural Sciences, Nanjing (China). Inst. of Agrobiological Genetics and Physiology)
Both the activities of superoxide dismutase (SOD) and catalase decreased markedly with the increase in NaCl concentration in the mediums and the prolonged duration of salinity treatments. A very significant correlation between enzyme activities and malondialdehyde (MDA), a product of membrane lipid peroxidation, was obtained. Varietal differences in response to different levels of NaCl were shown by changes in enzyme activities and MDA content. The activities of SOD and catalase in the tolerant variety were affected slightly at 0.2% NaCl. At higher NaCl concentrations (0.5% and 0.8%), the inhibition of activities of the two protective enzymes and the accompanying increase of MDA in the tolerant variety were less affected than those in the intolerant one. Studies also indicated that lower Na+ content and higher K+ : Na+ ratio may play an important role in the difference of tolerance. It is suggested that Na+ accumulation in the shoot could lead to the decrease of SOD and catalase activities, thus lowering the protective role against the active oxygen toxicity which may be regenerated in the plants under saline condition. Presumably, the salt tolerance of rice varieties is related to the inhibitory degree of the enzyme activities responsible for the protective and scavenging system to detoxify the active oxygen
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