豌豆灌浆期叶片抗氧化系统对土壤水分变化的响应

摘要

A pot experiment was conducted to investigate the response of pea ( Pisum sativum Linn. ) leaves antioxidant system to soil water in filling stage. Effect of different degree and duration drought stress and rewater under simulated conditions on the protective enzymes-superoxide dismutase (SOD) , catalase (CAT) and peroxidase (POD) activity, the cell materials-soluble protein, proline, soluble sugar and malonaldehyde (MDA) content, as well as plasma membrane permeability (RC) were determined. The antioxidant ability of pea leaves was also comprehensively evaluated. Results showed that drought stress declined SOD activity and soluble protein content, increased POD and CAT activity as well as proline,MAD and soluble sugar content, improved RC. And the decrease/ increase rate was more significant with increasing stress intensity and time. Rewater produced partial and equal compensation to protective enzymes,cell materials,MDA and RC changes caused by drought stress,and the compensation was more remarkable with rewater time. Total antioxidant ability of pea leaves enhanced under drought stress, and the trend had continued during rewater after 5 d stress,while for the 10 d drought stress treatment,the antioxidant ability presented decreasing trend at the time when rewater for 10 d. Consequently, moderate wetting-dry alternative irrigation was helpful for keeping stronger antioxidant ability, preventing from earlier senescence and obtaining higher yield.%为探求豌豆灌浆期叶片抗氧化系统对土壤水分变化的响应情况,采取盆栽土培人工控水试验方法,模拟了干旱胁迫及复水条件,测定了不同程度、不同历时的干旱胁迫和复水对豌豆灌浆期叶片保护酶-超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性和细胞内溶物-可溶性蛋白、脯氨酸、可溶性糖含量以及过氧化产物丙二醛(mDA)含量、脂膜相对透性(RC)的影响,并对叶片抗氧化能力进行了综合评价.结果表明:干旱胁迫导致豌豆灌浆期叶片SOD活性和可溶性蛋白含量降低,POD、CAT活性和脯氨酸、可溶性糖、MDA含量以及膜脂相对透性(RC)增加,且随干旱胁迫程度加重和胁迫历时延长降(增)幅加大；复水可对干旱胁迫所引起的叶片保护酶、细胞内溶物以及过氧化产物、膜脂相对透性的变化产生部分补偿效应或等量补偿效应,且随复水时间的延长补偿作用增强；干旱胁迫增强了豌豆叶片的综合抗氧化能力,历时5d的干旱胁迫处理复水后能够继续保持此趋势,但历时10d的干旱胁迫处理复水达到10d时抗氧化能力呈现降低趋势.因此,在豌豆灌浆期实行适度的“干湿交替”灌溉措施,有利于叶片保持较强的抗氧化能力,防止植株早衰,获得较高的经济产量.