Abstract: The effects of different soda salt-alkaline concentrations (20,25,30,35,40,45,50,55 and 60 mmol·L^-1) on the germination of WL343HQ and Longmu 807 alfalfa seeds were studied. The results showed that the germination rate,germination potential,germination index,vigor index and embryo length,radicle length,dry weight and fresh weight of the two species of alfalfa decreased with the increase of the concentration of soda salt-alkaline. Germination rate,germination potential and germination index in 40 mmol · L^-1 (WL343HQ) or 35 mmol · L^-1 (Longmu 807) soda salt-alkaline were less than 50%. Vigor index,bud length,root length,fresh weight,dry weight decreased significantly when treated with 40 mmol·L^-1 (WL343HQ) or 35 mmol·L^-1 (Longmu 807) soda saline. The concentration of soda salt-alkaline above 55 mmol·L^-1 inhibited the germination of alfalfa seeds. The seed germination rate was selected as the suitable concentration index of soda saline-alkali stress and linear regression was performed and determined the semi-lethal concentrations of WL343HQ and Longmu 807 seeds on soda saline-alkali stress were 42.41 mmol·L^-1 and 36.61 mmol·L^-1,respectively. The results of membership function analysis showed that the germination and seedling growth of WL343HQ seeds were higher than that of Longmu 807,and the resistance of WL343HQ to soda saline-alkali was higher than that of Longmu 807.

Key words: Alfalfa, Soda salt-alkaline stress, Seed germination, Membership function

摘要： 本试验以WL343HQ和龙牧807苜蓿（Medicago sativa L.）种子为试材，研究不同苏打盐碱浓度（20，25，30，35，40，45，50，55和60 mmol·L^-1）对苜蓿种子萌发的影响。结果表明：2种苜蓿种子随苏打盐碱胁迫浓度的增加发芽率、发芽势、发芽指数、活力指数和芽苗的胚芽长、胚根长、干重、鲜重均呈下降的趋势，发芽率、发芽势和发芽指数在苏打盐碱浓度为40 mmol·L^-1（WL343HQ）或35 mmol·L^-1（龙牧807）均低于50%，活力指数、芽长、根长、鲜重和干重在苏打盐碱浓度为40 mmol·L^-1（WL343HQ）或35 mmol·L^-1（龙牧807）时显著下降；苏打盐碱浓度超过55 mmol·L^-1抑制苜蓿种子萌发；以种子发芽率作为苏打盐碱胁迫适宜浓度指标的筛选并进行线性回归，确定WL343HQ和龙牧807苜蓿种子对苏打盐碱胁迫的半致死浓度分别为42.41 mmol·L^-1和36.61 mmol·L^-1。隶属函数分析结果表明：WL343HQ种子的萌发和芽苗生长各指标均高于龙牧807，WL343HQ抗苏打盐碱能力高于龙牧807苜蓿。

关键词: 苜蓿, 苏打盐碱胁迫, 种子萌发, 隶属函数