老芒麦成苗期间的耐旱性及其需水条件

Drought tolerance and water requirement of Elymus sibiricus in the period of seedling formation

为深入了解老芒麦旱境成苗机制,在不同渗透势的PEG-6000溶液条件下,比较研究了青藏高原高寒草地的主要建群种老芒麦(Elymus sibiricus L.)在种子萌动、发芽和出苗各不同成苗阶段的耐旱性及其对环境水势的最低需求。结果表明:1)随着水分亏缺的加重,老芒麦种子含水量呈下降的趋势,其萌动、发芽、出苗起始时间及其高峰期均出现滞后现象;复水后,老芒麦萌动、发芽和出苗高峰期仍存在滞后现象。2)水分亏缺抑制了青牧1号老芒麦种子萌发和幼苗生长;轻度水分亏缺可以促进15-195老芒麦种子萌发和幼苗生长,中度及以下的水分亏缺则具有抑制作用。3)随着水分亏缺的加重,老芒麦芽长呈下降的趋势,其根长、根芽比和根数逐渐增加;复水后,老芒麦芽长得到较大提高,其根长、根芽比和根数逐渐减少。4)老芒麦成苗各阶段对环境水势要求不同,且材料间的耐旱性也存在差异。

In order to further understand the seedling formation mechanism of E.sibiricus in drought stress environment,the drought tolerance of E.sibiricus at different seedling stages(such as:radicle emergence stage,germination stage and seedling emergence stage)and its minimum requirement for environmental water potential were studied under PEG-6000 solution with different osmotic potentials.The results were as follows:1)With the aggravation of water deficit,the seed water content of E.sibiricus showed a downward trend,the start time and its peak period of E.sibiricus in the period of bud,germination and seedling emergence all appeared lag phenomenon,and the peak period in the each seedling stage of E.sibiricus were still appeared lag phenomenon after rewatering.2)Water deficit inhibited the seed germination and seedling growth of Qingmu No.1 E.sibiricus.Mild water deficit could promote seed germination and seedling growth of 15-195 E.sibiricus,while moderate water deficit and lower water deficit had inhibitory effect.3)With the aggravation of water deficit,the bud length of E.sibiricus decreased,and its root length,root-bud ratio and root number increased gradually.4)There are different requirements for environmental water potential in different stages of seedling formation of E.sibiricus,and the drought tolerance among the materials are also different.