| Summary: | 碩士 === 國立中興大學 === 農藝學系 === 89 === Abstract
The effect of paraquat-induced oxidative damage on membrane and protein in detached edible soybean (Glycine max L. cv Kaohsiung selection no.1) cotyledon and unifoliate leaves was investigated.
Paraquat-induced oxidative strength increased with concentration and time. It was found to be effective in decreasing chlorophyll and protein levels, increasing lipid hydroperoxides, and then altered membrane permeability. Toxic oxygen radicals generated by paraquat rapidly react with membrane components and led to major electrolyte and solute leakages, decreased markedly total sugar, amino acids, ascorbate, glutathione, and thiol content in treated leaves. Vital fluorescent dyes, fluorescein diacetate also supports the membrane integrity changes under paraquat-mediated oxidative damage.
Paraquat treatment resulted in an increase in protein carbonyl content, and caused further degradation of oxidative protein. Using SDS-PAGE, it was found that paraquat induced both quantitative and qualitative changes in protein pattern. Although unifoliate leaves contain much of antioxidants, but unifoliate leaves were found to be more sensitive to paraquat-induced oxidative damage than cotyledon. Differential sensitivity to the oxidant paraquat may be partially attributed to the differences in tissue structure and cell components, or partially to the difference in antioxidant ability.
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