温度和水分对醉马草种子萌发的影响

为解释醉马草(Achnatherum inebrians(Hance)Keng)种群繁殖扩散机理,并为其开发利用提供理论基础,本文在不同温度和水分条件(PEG6000)下研究醉马草种子的萌发特性。结果表明:30℃、25℃和30/20℃(8h高温/16h低温)温度条件下醉马草种子萌发较快,25/5℃、20/5℃、20/10℃条件下萌发较慢,10℃和15/5℃条件下萌发速率最慢,在5℃条件下无萌发。在供试温度中,发芽率最高的处理为20℃、15℃和25/5℃,在此温度条件下的发芽率分别达96%、94%和94%。结合发芽率和幼苗生长,萌发最佳温度为20℃。醉马草种子的发芽率随着水分渗透势的降低而呈直线下降趋势,当渗透势<-1.5MPa时,无种子萌发。随着水分胁迫的加剧,供试种胚芽长呈逐渐下降趋势,但胚根长呈先增加而后下降的趋势,说明在轻度干旱条件下醉马草更多的生物量用于根部生长,从而能够吸收较深土壤的水分,对其在降雨后地表变干的生境中存活具有重要意义。

Effect of Temperature and Moisture Condition on Seed Germination of Achnatherum Inebriants(Hance)Keng

Achnatherum inebrians(Hance)Keng is a perennial poisonous weed that distributes in natural grassland of North China.In order to provide the basic information for its utilization and explain the mechanism of population propagation and dispersal,seeds germination characteristics of A.inebrians were studied under different treatments of temperature and moisture condition(PEG6000).The results show that seed germination rate was higher at 30℃,25℃ and 30/20℃(8h high temperature/16 h low temperature),lower at 25/5℃,20/5℃,and 20/10℃,lowest at 10℃ and 15/5℃,and no seed germinated at 5℃.For all temperature treatments,the highest germination percentages were 96%,94% and 94% at 20℃,15℃ and 25/5℃,respectively.Considering the germination rate and seedling growth,the optimum germination temperature was 20℃.The germination rate declined along with the osmotic potential decreased from 0 to-1.2 MPa,and no seed germinated when water osmotic potential was less than-1.5 MPa.The plumule growth was gradually prohibited as the osmotic potential decreased,however the radical growth was promoted from 0 MPa to-0.3 MPa and then decreased.Thus under light drought stress,A.inebrians may distribute more biomass for root growth to use the water from deep soil.This phenomenon is very important for plant survival in habitats with dry soil surface.