外源亚精胺对高温下黄瓜幼苗叶片抗氧化系统的影响

Effects of Exogenous Spermidine Pretreatment on Antioxidant System in Cucumber Seedling Leaves under High Temperature Stress

以黄瓜热敏感品种‘长春密刺’和耐热品种‘津春4号’为试材,在人工气候箱内采用营养液栽培法研究了外源亚精胺(Spd)预处理对短期高温胁迫(42℃)下黄瓜幼苗叶片抗氧化系统的影响。结果显示:(1)随高温胁迫时间的延长,2个黄瓜品种幼苗叶片相对电导率升高、MDA含量增加,热敏感品种的膜脂过氧化程度大于耐热品种;高温胁迫4h,SOD活性降低,POD、CAT、APX活性升高,抗坏血酸(AsA)含量升高,类胡萝卜素(Car)含量降低,且随胁迫时间反映出耐热品种抗氧化系统的自我调节能力大于热敏感品种。(2)外源Spd预处理能有效抑制高温胁迫引起的膜脂过氧化伤害,增强SOD、POD、APX活性以及AsA和Car含量,增强植株抗氧化能力,且在热敏感品种上的应用效果优于耐热品种。研究表明,外源Spd预处理能有效提高黄瓜幼苗叶片处于高温胁迫时的抗氧化能力,对缓解高温胁迫有重要作用。

The experiment was carried out by two cucumber cultivars ＇Changchun Mici＇ and ＇Jin Chun No 4＇ with different heat-tolerance in climate chambers and hydroponics to investigate the negative effects of high temperature（42℃） on antioxidant system of seedling leaves and the positive effects of exogenous spermidine pretreatment.The results showed that：（1） with stress time prolonged,the plasma membrane permeability elevated,MDA content increased,the antioxidative enzymes（SOD,POD,CAT and APX） activities and the oxidation inhibitor（ascorbic acid and carotenoids） contents changed,comparing with heat-sensitive ＇Changchun Mici＇,heat-resistant ＇Jin Chun No.4＇ was less affected by heat stress and had a stronger self-adjustment ability of antioxidant system.（2）The membrane lipid peroxidation under high temperature was suppressed by exogenous Spd pretreatment,protective enzymes activity of SOD,POD and APX,as well as the contents of ascorbic acid and carotenoids were enhanced to improve the total antio...更多xidant capacity of plants.These indicated that exogenous Spd pretreatment can improve cucumber antioxidant capacity under heat stress,especially for the heat-sensitive variety ＇Changchun Mici＇.