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为了研究苜蓿叶片表面蜡质与不同苜蓿品种抗旱性的关系,试验以5种抗旱性不同的苜蓿品种为材料,采用聚乙二醇(PEG)渗透胁迫的方法,对苜蓿幼苗叶片的相对含水量、脯氨酸含量和过氧化物酶(POD)活性进行测定;通过扫描电镜观察叶片表面蜡质覆盖情况,以三氯甲烷法抽提和测定叶片表面蜡质含量。结果表明:5种苜蓿叶片在PEG渗透胁迫下苜蓿叶片的相对含水量降低,脯氨酸含量增加,龙牧801、草原1号和敖汉苜蓿叶片的POD活性增加,龙牧81和皇后降低。抗旱性强的草原1号和敖汉苜蓿的叶片蜡质含量比较高,不同品种苜蓿叶片上表皮都有蜡质覆盖,蜡质密度不同,其中草原1号苜蓿叶片上下表皮均有蜡质覆盖,敖汉苜蓿叶片上表皮蜡质覆盖较密集,龙牧81和皇后苜蓿叶片上表皮蜡质的覆盖较稀疏。叶片表面蜡质出现线状、垂直片状、网状三种形态。从苜蓿幼苗的生理生化和蜡质含量综合分析,草原1号、敖汉抗旱性强,龙牧801居中,龙牧80和皇后抗旱性较弱。说明苜蓿品种叶片表面蜡质覆盖量与其抗旱能力呈正相关。
In order to study the relationship between the wax content on the surface of alfalfa and the drought resistance of different alfalfa cultivars, five alfalfa varieties with different drought resistance were used as materials. The relative water content of alfalfa seedling leaves , Proline content and peroxidase (POD) activity were measured. The wax coverage on the leaf surface was observed by scanning electron microscopy. The content of wax on the leaf surface was extracted and determined by chloroform method. The results showed that under the osmotic stress of PEG, the relative water content and the content of proline in leaves of five alfalfa varieties increased. The activities of POD in Longmu 801, grassland No.1 and alfalfa leaves increased, but those in Longmu 81 and queen decreased. The leaf wax content of the drought-tolerant Prairie No.1 and Ao-han alfalfa was relatively high. The upper epidermis of different varieties of alfalfa had waxy coverage and different wax density. The upper epidermis and the lower epidermis of alfalfa leaf No.1 were covered with wax, Aohan alfalfa leaves on the epidermal wax covering more intensive, Longmu 81 and Queensland alfalfa leaf epidermis wax sparse coverage. Leaf surface waxy appearance of linear, vertical sheet, mesh three forms. From the comprehensive analysis of the physiological, biochemical and waxy contents of alfalfa seedlings, the drought resistance of grassland No.1 and Aohan was strong, and Longmu 801 was the middle and Longmu 80 and the queen were weaker. The results showed that there was a positive correlation between the amount of wax covering on leaf surface and drought resistance of alfalfa cultivars.