UV-B辐射对蚕豆叶膜脂过氧化的影响及其机制

温室种植的吞豆在0（CK），8．82kJ/m2(T1)和12．6kJ/m2(T2)3种剂量的紫外线B（UV－B）辐射引起膜脂变化及其机制的研究结果表明，UV0B处理后，蚕豆叶片中丙二醛（MDA）和H2O2含量升高，膜脂肪酸不饱和度指数（IUFA）降低，脂氧合酶（LOX）活性升高，超氧歧化酶（SOD）活性稍有波动，而3种多胺－腐胺（Put)精胺（Spd)和尸胺（Spn)在照射7天后均有积累，但在处理后期（21d)有所回落，推测由LOX主导的酶促膜过氧化作用和氧自由基引起的非酶促过作用在膜结构的破坏中起重要作用，SOD活性和多胺含量的变化蚕豆对UV－B胁迫的一种适应性生理反应。

The effect of UV-B radiation on membrane lipid peroxidation and mechanisms in broad bean leaves

The changes and mechanism of membrane lipids in the broad bean leaves exposed to 0(CK)、8.82kJ/m2(T1) and 12.6kJ/m2（T2） of UV-B radiation were observed respectively.The results showed that the contents of malonaldehyde (MDA) and H2O2 were increased,and that of index of unsaturated fatty acid (IUFA) was decreased,lipoxygenase (LOX) activity was enhanced and superoxide dismutase (SOD) activity was slightly changed after UV-B radiation treatment.The diamine putrescine (Put),the polyamine spermidine (Spd) and spermine (Spn) were accumulated in the broad bean leaves after 7 days of UV-B radiation treatment and they were returned to normal after 21 days.Those results indicate that the membrane lipid peroxidation catalyzed by LOX and caused by oxygen radiacals,play an important role in the damage of the membrane structure.The changes of SOD activity and polyamine content in the broad bean leaves may be an adaptive physiological response to the UV-B radiation treatment.