盐旱交互胁迫对多花黑麦草(Lolium multilorum)种子萌发及胚生长的影响

为了揭示多花黑麦草(Lolium multilorum)对岩溶地区钙盐、干旱环境的适应机制,本研究采用不同浓度(0,5%,10%,15%,20%)聚乙二醇(PEG-6000)的干旱胁迫和不同浓度(0,5 mmol/L,10 mmol/L,25 mmol/L,50 mmol/L,100 mmol/L)CaCl2的钙盐胁迫,探讨干旱、钙盐及盐旱交互胁迫对多花黑麦草种子萌发及胚生长的影响。结果表明:随单一胁迫及交互胁迫浓度的增加,发芽势、发芽率、发芽指数呈先增后减的趋势,活力指数则不断下降。PEG浓度为10%时对多花黑麦草发芽率和发芽指数有促进作用;CaCl2浓度为5 mmol/L时对多花黑麦草的发芽势、发芽率和发芽指数有促进作用;5%PEG+10 mmol/L CaCl2交互胁迫下的发芽势、发芽率、发芽指数均较对照有所提高(p<0.05)。干旱胁迫下的胚芽长随胁迫浓度的增加呈先增后减的趋势,交互胁迫下胚根长及胚芽长均随胁迫浓度的增加而降低,15%PEG+100 mmol/L CaCl2、20%PEG+(5~100 mmol/L)CaCl2交互胁迫下种子不能萌发。本研究发现,岩溶区域低浓度的单一盐、旱胁迫和交互胁迫均对多花黑麦草种子的萌发有促进作用,干旱程度是影响该区域种子萌发和胚生长的限制性因子。本研究对多花黑麦草在岩溶地区的推广、种植有重要的指导意义。

Effects of Interactions between Ca^2+-salt and Drought Stress on Seed Germination and Embryo Growth of Lolium multilorum

The research aimed to explore the adaptation mechanisms of Lolium multilorum to high levels of calcium salts and drought areas in karst areas,effects of drought stress(0,5%,10%,15%,and 20%;PEG-6000)and Ca^2+-salt(0,5 mmol/L,10 mmol/L,25 mmol/L,50mmol/L,and 100 mmol/L)and their interactions on seeds germination and embryo growth of Italian ryegrass were conducted.Results showed that the germination potential,germination rate and germination index increased under lower concentration and then decreased with the increasing of the concentration of single and mutual stress,while vigor index decreased continuously.Germination rate and germination index of annual ryegrass were promoted by 10%PEG,germination potential,germination rate and germination index of annual ryegrass were promoted by 5 mmol/L CaCl2.Germination potential,germination rate,and germination index were improved under treatment of 5%PEG+10 mmol/L CaCl2 compared with CK(p<0.05).The germ length under drought stress increased first and then decreased with the increasing of stress concentration.The root length and germ length under interactive stress decreased with the increasing of stress concentration,and the seeds could not germinate under the treatments of 15%PEG+100 mmol/L CaCl2 and 20%PEG+5~100 mmol/L CaCl2.This study found that low levels of Ca^2+-salt and drought stress and their interaction can promote the germination,while the degree of drought stress is the limit factor to influence the seed germination and embryo growth of Italian ryegrass in Karst areas.The results of this study has important guiding significance for the popularization and planting of Italian ryegrass in karst area.