我国西北地区3个广泛种植苜蓿品种的萌发和生长对干旱胁迫的响应

采用聚乙二醇(PEG-6000)进行水分渗透胁迫,模拟研究了不同干旱胁迫环境对我国西北地区3个广泛种植的苜蓿品种:甘农一号杂花苜蓿(Medicago varia cv.Gannong No.1)、牧歌紫花苜蓿(Medicago sativa cv.Amerigraze401+Z)、新疆大叶紫花苜蓿(Medicago sativa cv.Xinjiang Daye)的萌芽和幼苗部分保护酶活性及幼苗叶片含水量的影响。结果表明,随着PEG-6000浓度的升高(PEG-6000浓度5%~25%),甘农一号杂花苜蓿、牧歌紫花苜蓿、新疆大叶紫花苜蓿的种子萌芽、幼苗叶片含水量及部分保护酶活性皆受到不同程度的影响。其中,3个苜蓿品种的发芽率、发芽指数、活力指数、发芽势皆明显降低,幼苗叶片含水量基本无显著变化,幼苗本体保护酶活性变化各不相同。利用隶属函数法分析得出3个苜蓿品种种子萌发期抗旱性强弱次序为:甘农一号杂花苜蓿>新疆大叶紫花苜蓿>牧歌紫花苜蓿,根据综合评价均值来看,甘农一号杂花苜蓿和新疆大叶紫花苜蓿抗旱性较强,而牧歌紫花苜蓿稍弱。

Responses of Germination and Growth of Three Varieties of Alfalfa Widely Cultivated in Northwest China against Drought Stress

In this study,the effects of different drought stress environments on bud of seeds,protective enzyme activity of seedlings and water content of seedling leaves of three varieties of alfalfa widely cultivated in Northwest China,including Medicago varia cv.Gannong No.1,Medicago sativa cv.Amerigraze401+Z,and Medicago sativa cv.Xinjiang Daye,were assessed under an artificially simulated osmotic stress condition prepared with polyethylene glycol(PEG-6000).The results showed that with the elevation of PEG-6000 concentrations(5%-25%),the bud of seeds,protective enzyme activity of seedlings and water content of seedlings leaves of the three tested varieties of alfalfa were affected in varying degrees.The germination rate,germination index,vigor index and germination potential of the three tested varieties of alfalfa were found obviously reduced,the water content of seedling leaves had no significant changes,and the changing features of the protective enzymes activity of seedlings were different.The membership function analysis demonstrated that the descending order of the drought resistance in the seed germination period of the three tested varieties of alfalfa was Medicago varia cv.Gannong No.1,Medicago sativa cv.Xinjiang Daye,and Medicago sativa cv.Amerigraze401+Z.According to the mean value of comprehensive evaluation,the alfalfa varieties of Medicago varia cv.Gannong No.1 and Medicago sativa cv.Xinjiang Daye had stronger drought resistance than Medicago sativa cv.Amerigraze401+Z.