摘要
选取适宜于“三江源”地区寒旱环境生长的垂穗披碱草为试验材料,采用纸上发芽法,利用高分子渗透剂聚乙二醇(PEG-6000)配制成-0.15、-0.30、-0.50、-0.75和-1.00 MPa溶液模拟干旱胁迫,以超纯水(0 MPa)溶液为对照组,研究了垂穗披碱草在成苗期间的耐旱性及其发芽出苗阶段的需水阈值。结果表明,干旱胁迫降低了种子发芽出苗率和发芽出苗速率。推迟了种子群体发芽、出苗的高峰期,且复水后种子发芽出苗高峰期同样存在推迟现象;垂穗披碱草种子发芽率、出苗率、发芽指数和活力指数、芽长、芽干鲜重和干物质积累率均随水分亏缺的加重呈下降的趋势,根长和根干鲜重则随水分亏缺的加重呈先升后降趋势;复水后,垂穗披碱草种子发芽率、出苗率、发芽指数、活力指数随着水分亏缺的加重呈先升后降的趋势,而根长、芽长及根芽干鲜重则呈下降的趋势;干旱胁迫对垂穗披碱草幼苗根的伸长影响较小,但对芽的伸长影响较大,且随着水分亏缺的加重而越发明显,从而使幼苗根芽比不断增加;垂穗披碱草发芽阶段与出苗阶段对环境水势的要求不同,发芽阶段的耐旱性较强。垂穗披碱草在成苗期间具有较强的耐旱性,且干旱后复水对垂穗披碱草种子发芽、出苗具有积极作用,即使重度(-0.50 MPa)干旱胁迫,复水后种子仍可大量发芽、出苗。本研究对于进一步探讨垂穗披碱草干旱适应机理具有重要理论研究价值,同时对利用垂穗披碱草有效防治“三江源”地区草地退化、沙化及水土流失具有重要的现实意义。
Elymus nutans is a suitable forage grass for growing in the cold and semi-arid environment in the Three River Headwaters region.In this study,we evaluated the drought tolerance and water demand threshold values of E.nutans during the germination and seedling establishment stages.For these analyses,seeds were germinated on paper under drought conditions simulated using the polymer polyethylene glycol(PEG-6000).Solutions of PEG-6000(-0.15,-0.30,-0.50,-0.75 and-1.00 MPa)were prepared to impose different levels of drought stress,with ultrapure water(0 MPa solution)as the control.The main findings were as follows:drought stress reduced the seed germination emergence percentage and germination emergence rate of E.nutans,delayed the peak period of seed germination and seedling emergence,and also delayed the peak period of seed germination and seedling emergence after re-watering.The seed germination percentage,seedling emergence percentage,germination index,vigor index,bud length,dry and fresh weight of buds,and dry matter accumulation of E.nutans decreased with increasing severity of drought stress.The root length and dry and fresh weight first increased and then decreased with increasing severity of drought stress.After re-watering,the seed germination percentage,seedling emergence percentage,germination index,and vigor index of E.nutans first increased and then decreased with increasing severity of drought stress,while the root length,bud length,and dry and fresh weight of root and buds decreased.Drought stress had little effect on the root elongation of E.nutans,but strongly affected bud elongation,and this effect became stronger with increasing severity of drought stress.Consequently,the root to shoot ratio of seedlings increased continuously with increasing severity of drought stress.The water demand threshold values of E.nutans varied during the period of germination and seedling emergence stages showed different requirements on environmental water potential.The germination stage had strong drought tolerance.Re-w
作者
王传旗
刘文辉
张永超
周青平
WANG Chuan-qi;LIU Wen-hui;ZHANG Yong-chao;ZHOU Qing-ping(Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau,Qinghai Academy of Animal Science and Veterinary Medicine,Qinghai University,Xining 810016,China;Southwest University for Nationalities,Chengdu 610041,China)
出处
《草业学报》
CSCD
北大核心
2021年第9期76-85,共10页
Acta Prataculturae Sinica
基金
青海省科技厅重点实验室发展专项(2020-ZJ-Y03)
青海省科技厅基础研究项目(2018-ZJ-968Q)
“昆仑英才乡村振兴人才”专项农业农村科技攻关团队资助。
关键词
垂穗披碱草
发芽出苗
水分亏缺
复水
需水阈值
三江源区
Elymus nutans
germination and seedling emergence
water deficit
re-watering
water demand threshold value
Three-River Headwaters Region
