四种豆科牧草萌发期对干旱胁迫的响应及抗旱性评价

Response and drought resistance of four leguminous pastures to drought during seed germination

对陕北黄土高原主要的4种豆科牧草毛苕子、沙打旺、白花草木樨、尖叶胡枝子种子生物学特性及干旱胁迫条件下种子萌发特性进行了研究。结果表明,1)4种植物种子生物学特性各异,沙打旺和毛苕子种子含水量、累计吸水率均大于其他2种,尖叶胡枝子和毛苕子的种子活力大于沙打旺和白花草木樨;2)随着干旱胁迫程度的加剧,4种植物种子总萌发率、幼苗鲜重、抗旱指数及胚根和胚芽的生长均呈下降趋势,且白花草木樨下降幅度最大;3)低浓度的PEG-6000对尖叶胡枝子的种子萌发、沙打旺的胚芽生长以及它们的抗旱指数均具有一定的促进作用;4)采用隶属函数法对干旱胁迫下4种植物萌发期抗旱性进行了综合评价,结果显示,4种植物种子萌发期的抗旱性次序为:毛苕子>尖叶胡枝子>沙打旺>白花草木樨。

The biological and germination characteristics of four Leguminous pasture plants （Vicia villosa, Astragalus adsurgens, Melilotus albus, Lespedeza hedysaroides） on the Loess Plateau were studied when under water stress. 1） The four species had different biological seed characteristics. Seed water content and seed im- bibition rates of A. adsurgens and V. villosa were higher than those of the other two species while seed vitality of L. hedysaroides and V. villosa were higher than the others. 2） As the drought intensified, total seed germi- nation rate, seedling fresh weights, drought resistance index, growth of radical and plumule of the four species declined with M. albus showing the largest decline. 3） The low content PEG-6000 improved seed germination of L. hedysaroides; seedling growth of A. adsurgens, and those of the drought resistance index. 4） The comprehensive evaluation of the four species by the membership function method indicated that the drought resistances decreased in the order V. villosa, L. hedysaroides, A. adsurgens, and M. albus.