摘要
在植物生长箱与田间条件下研究了冻害和热害对油菜植株抗氧化酶活性、脂质过氧化及膜损伤的影响．冻害处理使油菜叶片膜脂不饱和程度提高，而热害则使膜脂不饱和程度下降．冻害能使叶片ＳＯＤ活性显著提高，而ＣＡＴ与ＰＯＤ活性下降；热害则使叶片ＳＯＤ与ＰＯＤ活性下降，而对ＣＡＴ活性影响不大．冻害或热害处理均能提高油菜内源游离脯氨酸含量、电解质外渗率及脂质过氧化作用，而叶片叶绿素含量与根系活力则显著下降．热害和冻害引起的叶片脂肪酸组分变化、抗氧化酶活性与膜完整性的丧失以及叶绿素的降解，表明植株体内有氧自由基积累，从而引起植物伤害．冻害处理的油菜能缓慢地恢复生长，而热害处理的植株生长较差，热害处理两个月后逐渐死亡．
A study on the effects of freezing and heat stresses on enzyme activity and lipid peroxidation in winter rape was conducted in a growth chamber and the field condition The mean unsaturation of leaf fatty acids was increased following freezing stress, but decreased by heat stress A significant increase in leaf SOD and reduction in CAT and POD activities were observed following freezing stress On the contrary, heat stress significantly decreased SOD and POD activities but did not affect CAT activity Both the freezing and heat stressed plants had higher endogenous free proline content, rate of electrolyte leakage, and level of lipid peroxidation Both stresses significantly reduced leaf chlorophyll content and root oxidizability Heat and freezing induced changes in fatty acid composition, loss of antioxidant enzyme activities and membrane integrity, and chlorophyll degradation suggested the involvement of toxic oxygen species, which may in part be the cause for plant damage Freezing stress damaged the seedlings, but plants generally recovered at the later stage of growth Heat stressed plants were seriously damaged and grew poorly and gradually died in two months after heat treatment
关键词
油菜
冻害
热害
抗氧化酶活性
脂质过氧化
Brassica napus L
freezing
heat
antioxidant enzyme
lipid peroxidation
