4个紫花苜蓿品种萌发期抗旱性比较

Comparison of drought resistance among four alfalfa cultivars during germination

摘要:

为对比甘肃广泛种植的4个紫花苜蓿品种(甘农1号、新疆大叶苜蓿、中苜1号和中天1号)萌发期的抗旱性,采用不同浓度聚乙二醇6000(Polyethylene glycol 6000,PEG-6000)模拟干旱胁迫的方法,测定4个紫花苜蓿品种的种子在干旱胁迫下的发芽势、发芽率、发芽指数、抗旱指数和根芽比,并用隶属函数法对4个紫花苜蓿品种的萌发期抗旱性进行综合评价。结果表明:4个紫花苜蓿品种的种子的发芽势、发芽率和发芽指数在各个PEG浓度下均为新疆大叶苜蓿最大,根芽比和抗旱指数为甘农1号最大;随胁迫程度的加剧4个紫花苜蓿品种的种子的发芽势、发芽率、发芽指数和抗旱指数均呈下降趋势,而根芽比先升高后降低:PEG浓度为5%时最大,分别为甘农1号6.91、新疆大叶苜蓿3.68、中苜1号4.54和中天1号6.04,0%时次之;与PEG浓度为0%时相比,PEG浓度为5%时,中天1号的发芽势和发芽指数下降幅度最大,PEG浓度为25%时,新疆大叶苜蓿的发芽率和中天1号的抗旱指数下降幅度最大。萌发期综合抗旱性为甘农1号＞中苜1号＞新疆大叶苜蓿＞中天1号。

Abstract:

This study aimed to compare the drought resistance during the germination period among four alfalfa cultivars(Medicago sativa cv.Gannong No.1,Xinjiangdaye,Zhongmu No.1 and ZhongtianNo.1),which were widely planted in Gansu.The study used Polyethylene glycol 6000(PEG-6000) to simulate drought stress to determine the germination potential,germination rate,germination index,drought resistance index and root-shoot ratio.And the membership function method was used to comprehensively evaluate the drought resistance of the four alfalfa species during the germination period.The results showed that the germination potential,germination rate and germination index of the four alfalfa species were the greatest for cv.Xinjiangdaye under all PEG concentrations,while the drought resistance index and root-shoot ratio were the greatest in cv.Gannong No.1.The germination potential,germination rate,germination index and drought resistance index of the four alfalfa cultivars all decreased along with increasing concentration of PEG.The root-shoot ratio of alfalfa showed a trend of initial increase following by a decrease,and reached the maximum values at PEG concentration of 5%,with 6.91,3.68,4.54 and 6.04 for Gannong No.1,Xinjiangdaye,Zhongmu No.1 and Zhongtian No.1,respectively.Compared with the control(no PEG),germination potential and germination index decreased most in Zhongtian No.1 at 5% PEG,and germination rate in Xinjiangdaye and drought resistance index in Zhongtian No.1 decreased most at 25% PEG.The comprehensively drought resistance during the germination period followed an order of Gannong No.1 ＞ Zhongmu No.1 ＞ Xinjiangdaye ＞ Zhongtian No.1.Our results would provide guidance in the selection and planting of alfalfa in Gansu and possibly the entire northwestern region.