Shi Suyun, Wang Gang, Wang Yading, Zhang Lingang, Zhang Lixin
Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Nitric Oxide. 2005 Aug;13(1):1-9. doi: 10.1016/j.niox.2005.04.006.
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.
对菜豆叶片对UV - B辐射的响应进行了广泛研究。UV - B辐射导致菜豆叶片离子渗漏增加、叶绿素损失、PSII光化学最大效率（Fv/Fm）和PSII电子传递量子产率（PhiPSII）降低。随着UV - B辐射时间的延长，硫醇含量降低和羰基含量增加表明H2O2含量和类囊体膜蛋白氧化程度增加。添加一氧化氮（NO）供体硝普钠可部分缓解UV - B诱导的叶绿素含量、Fv/Fm和PhiPSII的降低。此外，NO减轻了对类囊体膜的氧化损伤。2 -（4 - 羧基苯基）- 4,4,5,5 - 四甲基咪唑啉 - 1 - 氧基 - 3 - 氧化物的钾盐，一种特异性NO清除剂，阻止了NO介导的对UV - B诱导的氧化损伤的保护作用。用浓度不断增加的H2O2孵育类囊体膜显示羰基含量逐渐增加。在UV - B辐射下，由于超氧化物歧化酶、抗坏血酸过氧化物酶和过氧化氢酶活性增加，NO存在时H2O2含量降低。综上所述，结果表明NO可能主要通过增强抗氧化酶活性有效地保护植物免受UV - B损伤。
