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Hung KT, Kao CH: Hydrogen peroxide is necessary for abscisic acid-induced senescence of rice leaves. J Plant Physiol. 2004 Dec;161(12):1347-57. The role of H2O2 in abscisic acid (ABA)-induced rice leaf senescence is investigated. ABA treatment resulted in H2O2 production in rice leaves, which preceded the occurrence of leaf senescence. Dimethylthiourea, a chemical trap for H2O2, was observed to be effective in inhibiting ABA-induced senescence, ABA-increased matondialdehyde (MDA) content, ABA-increased antioxidative enzyme activities (superoxide dismutase, ascorbate peroxidase, glutathione reductase and catalase), and ABA-decreased antioxidant contents (ascorbic acid and reduced glutathione) in rice leaves. Diphenyteneiodonium chloride (DPI) and imidazole (IMD), inhibitors of NADPH oxidase, and KCN and NaN3, inhibitors of peroxidase, prevented ABA-induced H2O2 production, suggesting NADPH oxidase and peroxidase are H2O2-generating enzymes in ABA-treated rice leaves. DPI, IMD, KCN, and NaN3 also inhibited ABA-promoted senescence, ABA-increased MDA contents, ABA-increased antioxidative enzyme activities, and ABA-decreased antioxidants in rice leaves. These results suggest that H2O2 is involved in ABA-induced senescence of rice leaves. |
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