5种禾草种子萌发及幼苗生长对干旱胁迫的响应和抗旱性评价

Response of seed germination and seedling growthof five grasses to drought stress and evaluationof their drought resistance

摘要:

为了解5种多年生禾草种子萌发期的抗旱性,采用聚乙二醇(PEG-6000)模拟干旱,分别以0,-0.05,-0.15,-0.30,-0.49 MPa PEG-6000溶液作渗透介质,研究了干旱胁迫对同德老芒麦、同德短芒披碱草、青海冷地早熟禾、青海草地早熟禾、青海中华羊茅5种禾草品种种子的发芽率、发芽势、发芽指数以及幼苗苗高、根长和干重等6个指标的影响。结果表明,随着PEG溶液渗透势降低,5种禾草种子发芽率、发芽势、发芽指数以及幼苗苗高和干重均呈现降低趋势,但各草种的不同指标响应不一致,未发现高渗透势介质对发芽有促进作用,但一定范围的渗透势对青海冷地早熟禾和青海中华羊茅幼苗根的生长有促进作用,而对其他3种禾草幼苗的根则有抑制作用。采用隶属函数法对5种禾草萌发期抗旱性综合评价的结果是同德老芒麦＞青海草地早熟禾＞短芒披碱草＞青海冷地早熟禾＞青海中华羊茅。

Abstract:

In order to investigate the drought resistance of 5 perennial graminoid grasses during the germination period,polyethylene glycol (PEG-6000) was used to simulate drought stress.A series of PEG-6000 concentrations,0,-0.05,-0.15,-0.30,-0.49 MPa,were used as osmotic media.The perennial graminoid studied were Elymus sibiricus cv.Tongde,Elymus breviaristus cv.Tongde,Poa crymophila cv.Qinghai,Poa pratensis cv Qinghai and Festuca sinensis cv Qinghai.The germination rate,germination potential,germination index and shoot length,root length and dry weight of seedlings were used as indicators.The results showed that the seed germination rate,germination potential,germination index,shoot length and dry weight of the 5 grasses reduced with the decease of osmotic potential,but the response of different indicators of each grass was inconsistent.High osmotic potential media did not affect the germination,but promoted the growth of seedling roots of Poa crymophila cv.Qinghai and Festuca sinensis cv.Qinghai,and inhibited the roots of the other three grass seedlings.The Membership Function showed that the overall drought resistance of the five grasses during the germination period was ranked as:Elymus sibiricus cv.Tongde＞Poa pratensis cv.Qinghai＞Elymus breviaristus cv.Tongde＞Poa crymophila cv.Qinghai＞Festuca sinensis cv.Qinghai.