摘要:采用不同渗透势聚乙二醇（PEG6000）溶液模拟干旱胁迫，研究了甘肃景泰、陇西、镇原、永昌、天水、榆中、宁县、夏河、临夏、渭源和内蒙古土默特、陕西陇县12个扁蓿豆（Medicago ruthenica）居群种子萌发期的抗旱性。结果表明，PEG胁迫降低了扁蓿豆种质资源的发芽率、发芽指数、活力指数，抑制了胚芽和胚根的生长。-0.3 MPa的渗透势胁迫可促进陇西扁蓿豆种子的萌发，且在此浓度下其相对发芽指数和相对活力指数均显著高于其他11份材料。在-0.3 MPa PEG胁迫下景泰和土默特扁蓿豆的相对胚根长较高，表现出一定的抗旱性；高渗透势的胁迫严重抑制了扁蓿豆胚芽和胚根的生长。以种子萌发期的相对发芽率、相对发芽指数、相对活力指数、相对胚根长和相对胚芽长等5项为指标，应用隶属函数法对12份扁蓿豆抗旱性进行综合评价，抗旱性强弱依次为：景泰＞陇西＞土默特＞镇原＞永昌＞天水＞榆中＞宁县＞夏河＞临夏＞陕西陇县＞渭源。

关键词:扁蓿豆  萌发期  PEG胁迫  隶属函数

AbstractDrought resistances were evaluated based on seeds germination stage under different osmotic potential of polyethylene glycol (PEG 6000) among 12 accessions of Medicago ruthenicac collected from Jingtai, Longxi, Zhenyuan, Yongchang, Tianshui, Yuzhong, Ningxian, Xiahe, Linxia and Weiyuan of Gansu Prvience, Tumote of Inner Mongolia, and Longxian of Shanxi. The results showed that the germination rate, germination index and vigor index of M. ruthenica decreased, and the growth of plumule and radical were inhibited under PEG stress. The seed germination of M. ruthenica (Longxi) was improved by draught stress of -0.3 MPa osmotic potential, and the relative germination index and relative vigor index were significantly higher than other 11 materials under this concentration. The relative radical length of M. ruthenica(Jingtai) and M. ruthenica (Tumote) were higher than others under draught stress of -0.3 MPa osmotic potential, which showed some drought resistance. The growth of radical was seriously inhibited under high osmotic potential stress. Based on the relative germination rate, relative germination index, relative vigor index, relative plumule length and relative radical length, The comprehensive evaluation of 12 accessions of M. ruthenica by the subordinate function method indicated that the drought resistance ability were ranked as Jingtai＞Longxi＞Tumote＞Zhenyuan＞Yongchang＞Tianshui＞Yuzhong＞Ningxian＞Xiahe＞Linxia＞Longxian (from Shanxi）＞Weiyuan.

Key wordsMedicago ruthenica  seed germination  PEG stress  subordinate function

文章编号： 0258_7106 (2016) 01_0018_15 中图分类号： P618.41 文献标志码：A

改回日期：2015_07_11

基金项目

**通讯作者耿新霞， 女， 1979年生， 助理研究员， 成矿规律研究方向。 Email： gen gxinxia@cags.ac.cn