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渗透胁迫下稻苗中铁催化的膜脂过氧化作用

蒋明义, 郭绍川

湘潭师范学院生物系.湖南,湘潭 411201

摘要

在-0.7MPa渗透胁迫下,水稻幼苗体内O~(.)_(2)和H_(2)O_(2)大量产生,Fe~(2+)积累,膜脂过氧化作用加剧。水稻幼苗体内Fe~(2+)含量与膜脂过氧化产物MDA含量呈极显著的正相关。外源Fe~(2+)、Fe~(3+)、H_(2O_(2)、Fe~(2+)+H_(2)O_(2)、DDTC均能刺激膜脂过氧化作用。·OH的清除剂苯甲酸钠和甘露醇能明显地抑制渗透胁迫下Fe~(2+)催化的膜脂过氧化作用。这都表明渗透胁迫下水稻幼苗体内铁诱导的膜脂过氧化作用主要是由于其催化Fenton型Haber-Weiss反应形成·OH所致。

关键词： 渗透胁迫; 铁离子; 羟自由基; 膜脂过氧化 ; 水稻幼苗

Iron-catalysed lipid peroxidation in rice seedlings under osmotic stress

Jiang Mingyi, Guo Shaochuan

Departhment of Biology,Xiangtan Teacher^s College.Xiangtan 411201,Hunan

Abstract

Seedlings of hybrid rice (Oryza sativa L.) were exposed to osmotic stress by PEG 6000 (-0.7 MPa) and the contents of ferrous iron(Fe~(2+)),hydrogen peroxide (H_(2)O_(2)) and malondialdehyde (MDA) and the rate of production of superoxide radical (O~(.)_(2)) were measured. Under osmotic stress, the increases of contents of Fe~(2+) and H_(2)O_(2) and H_(2)O_(2) and rate of O~(.))_(2) production were accompanied by an increase of content of MDA. A very correlation (P<0.01) was observed between Fe~(2+) content and MDA content. Pretreatment with Fe~(2+),Fe~(3+),H_(2)O_(2),Fe~(2+)+H_(2)O_(2) and the inhibitor of SOD, sodium diethyldithiocarbamate (DDTC), obviously promoted lipid peroxidation, but the iron chelator, di ethylenetriaminepentaacetic acid (DTPA), retarded the increase of MDA. Application of the hydroxyl radical scavengers, mannitol and sodium benzoate, markedly inhibited the lipid peroxidation of Fe~(2+) mediated under osmotic stress. These results indicate that iron-stimulated lipid peroxidation in rice seedlings is mainly due to the formation of highly reactive hydroxyl radical (·OH) by superoxide driven Fenton reaction catalysed by iron under osmotic stress, but a complex between oxygen and different valence states of iron has little effect on lipid peroxidation.

Key words: Osmotic stress;Iron ion;Hydroxyl radical;Lipid peroxidation;Rice seedlings

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引用本文：

蒋明义, 郭绍川. 渗透胁迫下稻苗中铁催化的膜脂过氧化作用[J]. 生理学报 1996; 48 (1): .

Jiang Mingyi, Guo Shaochuan. Iron-catalysed lipid peroxidation in rice seedlings under osmotic stress. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).