茉莉酸浸种对高温胁迫下多年生黑麦草种子发芽的影响

Effects of jasmonic acid pretreatment on perennial ryegrass seed germination under heat stress

以多年生黑麦草品种(Lolium perenne)‘麦迪’(Mathilde)和‘绅士’(Esquire)为供试材料,采用20、25、30、33℃共4个温度处理,研究不同高温对多年生黑麦草种子发芽的影响及不同浓度(5、10、20、40、60、80、100μmol·L–1)茉莉酸浸种提高多年生黑麦草在高温胁迫下种子发芽能力的生理效应。结果表明,高温胁迫在一定程度上影响了多年生黑麦草种子的发芽过程,随处理温度的升高,多年生黑麦草种子的发芽率、发芽势和发芽指数均显著下降(P<0.05),特别是对根长和幼苗的影响显著,且‘麦迪’显著优于‘绅士’。在高温胁迫条件下,浓度为40~60μmol·L–1的茉莉酸浸种显著提高了多年生黑麦草种子的发芽能力,同时种子幼苗的超氧化物歧化酶活性与对照相比显著增高,丙二醛含量显著降低。适宜浓度茉莉酸浸种可以在一定程度上减缓高温胁迫对多年生黑麦草种子发芽的影响,有效提高多年生黑麦草种子在高温胁迫下的发芽能力和种子幼苗活性。

Using perennial ryegrass varieties‘Mathilde’and‘Esquire’as test materials,we evaluated the effects of different temperatures(20,25,30,and 33℃)and jasmonic acid concentrations(5,10,20,40,60,80,and 100μmol·L–1)on the seed germination of perennial ryegrass.To a certain degree,the results demonstrated that high temperature stress affected the germination characteristics of perennial ryegrass seeds.The germination rate,germination potential,and germination index of perennial ryegrass seeds decreased significantly with increasing temperature,especially affecting root and seedling length.Notably,the germination characteristics of‘Mathilde’were better than‘Esquire.’Under high temperature stress,the germination ability of perennial ryegrass seeds was significantly improved by soaking seeds in jasmonic acid concentrations between 40 and 60μmol·L^–1.Meanwhile,the superoxide dismutase(SOD)activity of the seedling significantly increased while the malonic dialdehyde(MDA)content decreased.Treatment with an appropriate concentration of jasmonic acid could efficiently improve the germination ability and activity of perennial ryegrass seeds under heat stress.