外源5-氨基乙酰丙酸对盐胁迫下菘蓝种子萌发及幼苗抗氧化酶活性的影响

采用砂培方式,研究了外源5-氨基乙酰丙酸(ALA)对盐胁迫下菘蓝种子的萌发、幼苗叶片的可溶性糖含量、丙二醛(MDA)含量及其抗氧化酶活性的影响,探讨ALA缓解菘蓝受盐胁迫伤害的响应机制。结果显示:(1)菘蓝种子萌发及幼苗生长在100 mmol·L^-1 NaCl胁迫下受到明显的抑制,种子发芽率、发芽势、发芽指数、活力指数与自然含水量均显著降低,丙二醛含量、可溶性糖含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性显著升高。(2)盐胁迫下适宜浓度的ALA处理显著提高了种子萌发率、自然含水量及SOD、POD和CAT活性,降低了可溶性糖和丙二醛的含量,并以16.7 mg·L^-1 ALA处理盐胁迫下菘蓝种子的发芽率、发芽势最大,其幼苗的SOD、POD、CAT活性最强。研究表明,盐胁迫显著抑制菘蓝种子的萌发及幼苗生长,适宜浓度的ALA能够有效缓解盐胁迫对菘蓝种子萌发及幼苗生长的伤害,提高植株的抗盐性,并以16.7 mg·L^-1 ALA处理效果最佳。

Effect of Exogenous 5-aminolevulinic Acid on Seed Germination and Antioxidase Activities of Isatis indigotica Seedlings under Salt Stress

We studied the effects of exogenous 5-aminolevulinic acid(5-ALA)on germination of seeds,the content of soluble sugar,malondialdehyde(MDA)and antioxidase activities in Isatis indigotica seedlings under salt stress with sand culture.The results showed that:(1)There were significant inhibition of seed germinating and seedling growth in 100 mmol·L^-1 of NaCl stress.Germination rate,germination vigor,germination index,vigor index of seeds and water content were significantly decreased under salt stress,while malondialdehyde (MDA),content of soluble sugar,Cu-Zn superoxide dismutase (SOD)and peroxidase (POD) activies were increased significantly.(2)Under salt stress,appropriate concentration ALA could improve germination rate,water content,activities of SOD,POD and CAT,meanwhile reduce the contents of soluble sugar and malondialdehyde (MDA),in which the germination rate and germination vigor of seeds were the maximum,and the activities of SOD,POD,CAT were the maximum by the treatment of 16.7 mg·L^-1 ALA.It indicated that salt stress could obviously inhibit the seed germinating and seedling growth.Appropriate concentration ALA could effectively alleviate the damage to seed germinating and seedling growth of I.indigotica under salt-stress and promote the salt resistance,especially the effect of 16.7 mg·L^-1 ALA was the most significant.