水分胁迫对皱果苋幼苗保护酶活性及生理指标的影响

Effect of Water Stress on Physiological Indicators and Activity of Defense Enzymes of Amaranthus viridis

[目的]研究水分胁迫对皱果苋幼苗叶片脯氨酸、丙二醛含量和保护酶活性的影响,探讨皱果苋耐旱机制。[方法]用浓度5%、10%和20%聚乙二醇-6000(PEG-6000)模拟水分胁迫的方法,分别处理0、1、3、5、7 d,取叶片测定各项生理生化指标。[结果]随水分胁迫时间的延长,皱果苋幼苗叶片中的脯氨酸和丙二醛含量增加;而抗氧化酶[超氧化物歧化酶(SOD)和过氧化物酶(POD)]的活性呈先升后降趋势。在浓度10%和20%PEG-6000胁迫1 d处理下SOD酶活性达到最大,分别为42.37 U/(gFW.h)和38.51 U/(gFW.h);而浓度20%PEG-6000胁迫下,其POD酶活性达到最大[14.9 U/(gFW.min)]。[结论]皱果苋叶片脯氨酸含量的增加和保护酶的变化对皱果苋耐旱和保护其细胞膜的完整性有一定作用。

[ Objective ] The effects on contents of proline, MDA and anti-oxidative enzyme activities in leaves of Amaranthus viridis L. were studied under water stress in order to discuss drought resistance mechanism. [ Method] The young plants of Amaranthus viridis L. were treated by PEG-6000 osmotic stress with concentrations of 5 %, 10% and 20% for 0, 1,3, 5, 7 days, and then leaves were taken out to measure the physiological and biological indices. [ Result] Along with time of water stress, the contents of proline and MDA increased. However, the activities of anti-oxidative enzymes （SOD and POD） increased at first, and then decreased. In 1 d, the activities of SOD inlO% and 20% PEG6000 respectively were 42.37 and 38.51 U/（ gFW · h） ; the activity of POD in 20% PEG-6000 was 14.9 U/（ gFW · min） ; [ Conclusion] The proline and two defense enzymes of Amaranthus viridis＇ leaves might play a key role in protecting integrity of membrane under water stress.