燕麦劣变种子吸胀过程中线粒体AsA-GSH循环的生理响应

Physiological Responses of Mitochondrial AsA-GSH Cycle to Imbibition of Deteriated Oat Seeds

为探究种胚线粒体抗坏血酸-谷胱甘肽(ascorbate-glutathione,AsA-GSH)循环响应老化的抗氧化作用机制,本试验通过控制劣变处理获得高活力和中活力燕麦(Avena Sativa.L)种子,以未老化种子作为对照,研究了吸胀过程中的发芽特性、种胚线粒体活性氧(reactive oxygen species,ROS)含量以及AsA-GSH循环酶活性和抗氧化物质的变化规律。结果显示,随着燕麦种子活力的下降,发芽率、活力指数、发芽指数、根长、苗长下降以及平均发芽时间增加。燕麦种子劣变主要通过降低AsA-GSH循环中抗坏血酸过氧化物酶(ascorbate peroxidase,APX)、谷胱甘肽还原酶(glutathione reductase,GR)活性以及GSH/氧化型谷胱甘肽(oxidized glutathione,GSSG)比值,使种胚线粒体内ROS积累,产生氧化损伤,继而对种子萌发和幼苗生长产生不良影响。

In this study,high vigor and medium vigor of oat seeds were obtained by controlled deterioration treatments,with the normal seeds as the control,to study germination characteristics,mitochondrial reactive oxygen species(ROS)contents,and ascorbate-glutathione(AsA-GSH)cycle enzyme activity and metabolites during the seed imbibition.It was aimed to explore the anti-oxidant response of AsA-GSH cycle in seed embryo mitochondria to aging.The results showed that the germination percentage,vigor index,germination index,root length,and shoot length decreased,and the mean germination time increased with the decreasing vigor of oat seeds.Oat seed deterioration resulted in ROS accumulation and oxidative damage in the mitochondria of the seed embryo by lowering ascorbate peroxidase(APX),glutathione reductase(GR)activities and GSH/oxidized glutathione(GSSG)ratio in AsA-GSH cycle,which in turn hurt seed germination and seedling growth.