title: Protective effect of nitric oxide against oxidative stress under ultraviolet-B radiation.
abstract: The response of bean leaves to UV-B radiation was extensively investigated. UV-B radiation caused increase of ion leakage, loss of chlorophyll, and decrease of the maximum efficiency of PSII photochemistry (Fv/Fm) and the quantum yield of PSII electron transport (PhiPSII) of bean leaves. H2O2 contents and the extent of thylakoid membrane protein oxidation increased, indicated by the decrease of thiol contents and the increase of carbonyl contents with the duration of UV-B radiation. Addition of sodium nitroprusside, a nitric oxide (NO) donor, can partially alleviate UV-B induced decrease of chlorophyll contents, Fv/Fm and PhiPSII. Moreover, the oxidative damage to the thylakoid membrane was alleviated by NO. The potassium salt of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger, arrested NO mediated protective effects against UV-B induced oxidative damage. Incubation of thylakoid membrane with increasing H2O2 concentrations showed a progressive enhancement in carbonyl contents. H2O2 contents were decreased in the presence of NO under UV-B radiation through increased activities of superoxide dismutases, ascorbate peroxidases, and catalases. Taken together, the results suggest that NO can effectively protect plants from UV-B damage mostly probably mediated by enhanced activities of antioxidant enzymes.
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Suyun
authors.initials: S
authors.lastname: Shi
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Yading
authors.initials: Y
authors.lastname: Wang
authors.forename: Lingang
authors.initials: L
authors.lastname: Zhang
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D004579:Electron Transport; D016166:Free Radical Scavengers / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000528:radiation effects; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D018384:Oxidative Stress / Q000528:radiation effects*; D010544:Peroxidases / Q000378:metabolism / Q000528:radiation effects; D027805:Phaseolus / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D045332:Photosystem II Protein Complex / Q000528:radiation effects; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism; D011837:Radiation-Protective Agents / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism / Q000528:radiation effects; D020524:Thylakoids / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D045332:Photosystem II Protein Complex; D011837:Radiation-Protective Agents; D002734:Chlorophyll; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase