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Effects of ultraviolet-B radiation on active oxygen metabolism and membrane system of rice leaves

Yan Bin, Dai Qiujie

The Institute of Agrobiological Genetics and Physiology, Jiangsu Academy of Agricultural Sciences. Nanjing 210014, Jiangsu

Abstract

Two rice cultivars (IR74 and Dular) were grown in a greenhouse for ten days and then treated with four levels of UV-B (0.0, 6.0, 13.0, 19.1 kJ m~(-2) d~(-1)) for 28 days in a glasshouse. UV-B radiation caused significant increased in electrolyte leakage, malindialdehyed (MDA) content and the net rate of O_(2) generation. These increases were greater in the sensitive cultivar Dular than in the less-sensitive cultivar IR74 under high radiation (13.0 and 19.1 kJ m~(-2) d~(-1)) and long UV-B exposure (28 days). The extents of the changes in O_(2) and MDA content were greater than those of electrolyte leakage and H_(2)O_(2) content. Ascorbate peroxidase activity was significantly reduced and other antioxidants (superoxide dismutase, catalase, ascorbic acid and glutathione) were enhanced during short exposure to UV-B radiation (14 days). SOD activity, however, was reduced after 14 day treatment. The less-sensitive cultivar retained a higher SOD activity than the sensitive one under high radiations. The parameters described above returned to levels similar to those of the control (0.0) after UV-B radiation (13.0) had been stopped for 14 days. Based on these results, it is deduced that UV-B injury to membrane may be correlated to excessive production of O~(.)_(2) which induces an increase in lipid peroxidation, while O~(.)_(2) accumulation may be caused by the inhibition of SOD. The varietal difference in UV-B sensitivity of rice cultivars may involve the difference in SOD level, which affects the rate of breakdown of O~(.)_(2).

Key words: Dryza sativa L;Ultraviolet-B;Membrane permeability;Lipid peroxidation;Active oxygen metabolism

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Citing This Article：

Yan Bin, Dai Qiujie. Effects of ultraviolet-B radiation on active oxygen metabolism and membrane system of rice leaves. Acta Physiol Sin 1996; 48 (4): (in Chinese with English abstract).