不同抗旱性玉米幼苗根系抗氧化系统对水分胁迫的反应

以抗旱性不同的2个玉米品种为材料，研究不同程度水分胁迫下玉米根系活性氧清除系统的变化及膜脂过氧化水平。明确了轻度水分胁迫下玉米根系POD、CAT、APX等保护酶活性明显提高；中、重度胁迫下其活性急剧下降，但几种酶对水分胁迫的敏感程度不同。SOD对水分胁迫表现最不敏感，在中度水分胁迫下仍保持上升趋势；抗氧化剂GSH含量变化趋势与保护酶相似；而AsA含量在不同程度水分胁迫下持续下降；MDA含量随水分胁迫程度加剧而增加。其中抗旱性强的鲁玉14与抗旱性弱的掖单13相比具有较高的保护酶活性和抗氧化剂含量，膜脂过氧化程度较轻，除POD外，品种间抗氧化酶活性（抗氧化剂含量）呈极显著差异，说明抗氧化能力强是抗旱性品种具有较强抗旱性的重要原因之一。

The response to water stress of the antioxidant system in maize seedling roots with different drought resistance

The level of lipid peroxidation and changes of activited oxygen scavenging system in two maize species with different drought resistance were studied.The results showed the activities of POD?CAT?APX?GR were obviously increased under light water stress,while decreased under middle and severe water stress,but the sensitive degree of these enzymes to water stress is different,the activity of SOD is still increased under middle water stress.The change of GSH content is similar to enzyme's,while the content AsA is declined constantly;the content of MDA is increased following the stronger water stress.The drought-resistn at variety Luyu No.14 has higher activity of enzymes,content of antioxidents and lower content of MDA than the drought-sensitive variety Yedan No.13.The differences of enzyme activities (except POD activity) and antioxiwdant contents between two species are very significance.This results that drought-resistant variety with stronger ability of antioxidant may be one of the important reasons of its higher tolerance.