水分胁迫下扁穗牛鞭草根系保护酶活性变化

Changes in protective enzyme activities in cells of Hemarthria compressa under water stress

在水分胁迫下,以国审扁穗牛鞭草品种广益和重高为材料,研究2种牧草根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量变化情况。结果表明,在水分胁迫期间,广益和重高扁穗牛鞭草根系MDA含量和SOD、POD、CAT活性迅速升高,在14d时达到最大值,之后MDA含量和3种保护酶活性均出现大幅度下降。研究还表明,初期MDA含量上升主要是由水分胁迫引起的,而3种保护酶活性的上升则主要是MDA含量上升所致。14d后MDA含量和3种保护酶活性的下降可能是由于2种扁穗牛鞭草在渡过干旱阈值期后,表现出一定耐受性和适应性。在研究期间,重高扁穗牛鞭草根系MDA含量始终高于广益,综合2种扁穗牛鞭草萎蔫和枯萎状况,表明广益扁穗牛鞭草抗旱能力大于重高扁穗牛鞭草。

Two national varieties ＂Guangyi＂ and ＂Chonggao＂ were used to study the changes of superoxide dis- mutase （SOD）, peroxidase isoenzyme （POD）, catalase （CAT） and malondialdehyde （MDA） in roots. The results showed that the MDA content and the activities of superoxide dismutase, peroxidase isoenzyme, and catalase in the roots increased during water stress, with a peak at 14 days. After that, the content of malondi- aldehyde and the activities of the three kinds of protective enzymes declined significantly. The study also showed that the initial rise in the content of malondialdehyde was mainly caused by drought stress. However, the rises in the three kinds of protective enzymes activities may result from the rise of malondialdehyde. After 14 days of drought stress, the reduction in content of the three protective enzymes may due to their tolerance and adaptability after experiencing the drought-threshold period. During the study, the roots of ＂Chonggao＂ always had a higher MDA than ＂Guangyi＂. Based on the drooping and wilting status of the two grasses, we conclude that ＂Guangyi＂ has a greater drought resistance than ＂Chonggao＂.