甜菜幼苗叶片抗氧化系统对干旱胁迫的响应

Response of Antioxidant System to Drought Stress in Sugar Beet Leaves at Seedling Stage

以抗旱性不同的甜菜品种HI0466和KWS9454为供试材料,在不同水分处理条件下研究了甜菜抗氧化系统生理指标对苗期不同程度水分亏缺的响应机制及其与甜菜抗旱性的关系。结果表明:持续水分胁迫下甜菜幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等保护酶活性及抗氧化物质还原型谷胱甘肽(GSH)、抗坏血酸(AsA)含量基本呈现出先升高后下降的趋势,而类胡萝卜素(Car)含量逐步降低。由于抗旱甜菜品种在水分胁迫下各生理指标具有增幅大或降幅较小的特征,因此在胁迫加重时抗旱甜菜品种可维持较高的SOD、POD、CAT活性及Car、AsA含量,以降低膜质过氧化程度,使得其丙二醛(MDA)含量维持在较低水平,但在品种间差异明显。主成分分析结果表明,干旱胁迫条件下SOD、POD活性,MDA、AsA含量均可作为甜菜品种苗期抗旱性鉴定的有效生理指标。

Two sugar beet cultivars HI0466 and KWS9454, different in drought resistance, were used to examine the response of antioxidant system to drought stress and the relationship for evaluating drought resistance during seedling stage under different drought conditions. The results showed that activities of protective enzymes SOD, POD, CAT and contents of GSH, AsA were increased significantly and then decreased significantly, however, carotenoids （Car） content decreased under drought stress. To resistant cultivar, the increase was more significant than the decrease, so the activities of SOD, POD and CAT and the contents of Car, AsA were higher, meanwhile, malondialdehyde （MDA） contents were lower under several treatments. There was significant difference between HI0466 and KWS9454. In addition, it was found that the activities of SOD, POD and contents of MDA, AsA could be used as effective indicators for the identification of drought resistance at seedling stage for sugar beet species by principal component analysis.