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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。
In order to study the response mechanism of different physiological indexes of sugar beet to water deficit at seedling stage and its relationship with drought resistance of sugar beet, HI0466 and KWS9454 with different drought resistance were used as tested materials. The results showed that the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and other protective enzymes in the leaves of beet seedling under continuous water stress and the content of GSH ), Ascorbic acid (AsA) showed a trend of first increasing and then decreasing, while the content of carotenoids gradually decreased. As drought-resistant sugar beet varieties have the characteristics of larger or smaller decrease of physiological index under water stress, drought-tolerant sugar beet varieties can maintain higher SOD, POD and CAT activities and Car, AsA content to reduce membrane quality The degree of peroxidation kept its content of malondialdehyde (MDA) at a low level, but the difference among varieties was obvious. Principal component analysis showed that the activity of SOD, POD and the contents of MDA and AsA in drought stress could be used as effective physiological indexes to identify the drought resistance of sugar beet seedlings.