渗透胁迫下外源茉莉酸甲酯对油菜种子生理特性的影响

采用PEG模拟水分胁迫的方法,研究在5%PEG-6000胁迫下,不同浓度(0.025、0.05、0.1 mmol·L-1)茉莉酸甲酯(MeJA)对油菜种子萌发、幼苗生长、叶片氧化损伤和保护酶活性等生理生化特性的影响.结果显示:0.1mmol·L-1MeJA处理能显著缓解5%PEG-6000的胁迫伤害,使油菜种子发芽率、发芽势、发芽指数和活力指数分别显著提高62.3%、11.2%、55.2%、126.3%,主根长度降低45.0%,不定根数提高59.4%,但对株高无显著影响;同时叶片MDA含量降低20.6%,SOD、CAT、POD和APX活性分别提高100.0%、109.1%、452.6%和134.8%.研究表明,MeJA在一定程度上能够缓解渗透胁迫的抑制作用,提高SOD等保护酶的活性,缓解渗透胁迫造成的氧化损伤,有效促进渗透胁迫下油菜种子的萌发和幼苗生长.

Effects of Exogenous MeJA on Physiological Characteristics of Brassica napus under Osmotic Stress

5% PEG-6000 was used to produce the osmotic pressure,under which the effects of exogenous MeJA at three concentrations of 0.025,0.05 and 0.1 mmol·L-1 were measured on seed germination,seedling growth,oxidative damage to leaves,and protective enzyme activities in Brassica napus.The results indicated that the damages to B.napus caused by the osmotic stress of 5% PEG-6000 were significantly relieved in the presence of 0.1 mmol·L-1 MeJA.The seed germination rate,germination potentiality,germination index,and vigor index increased by 62.3%,11.2%,55.2% and 126.3%,respectively.The length of main root decreased by 45.0%,and the number of adventitious roots increased 59.4%,MDA content decreased by 20.6%.The protective enzyme activities of SOD,POD,CAT,and APX increased by 100.0%,109.1%,452.6%and 134.8% in leaves,respectively.Based on the data reported,we conclude that to some extent MeJA can alleviate inhibitory effect under osmotic stresses effectively and stimulates B.napus seed germination and seedling growth.MeJA can also enhance the activities of protective enzymes and relief oxidative damage.