不结球白菜种子活力及抗氧化特性在人工老化过程中的变化

摘要

In this study, using non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis Makino. )variety 'Hanxiao' as material, we studied seed vigor and antioxidant-related indexes during artificial aging at 42℃ and RH 100％. The results showed that with the increase of aging time,the seed germination rate,germination energy, germination index and vigor index decreased, abnormal seedling rate after germination rose;The O2- production speed firstly went up and then went down;The hydrogen peroxide (H2O2) content kept increasing. The relative electrolyte leakage was increased and the contents of malondialdehyde (MDA) and activities of lipoxygenase (LOX) were decreased. While superoxide dismutase (SOD),catalase (CAT) and glutathione reductase (GR) declined gradually with the aging process. Both of the ascorbate peroxidase (APX) and glutathione peroxidase (GPX) activities increased during the initial phase of artificial aging,APX activity decreased afterward,while the GPX activity showed no obvious change;The contents of antioxidant ascorbic acid (ASA) and glutathione (GSH) dropped significantly after 1 d-aging,then no remarkable change afterward. It suggested that the disorder of antioxidant system led to reactive oxygen metabolism imbalance, this might be the major cause leading to seed aging in non-heading Chinese cabbage.%以不结球白菜品种'寒笑'种子为材料,研究高温(42℃)高湿(相对湿度 100%)人工老化处理过程中种子活力及抗氧化相关特性的变化.结果显示:不结球白菜种子的发芽率、发芽势、发芽指数和活力指数随老化处理时间的延长而逐渐下降,不正常苗率逐渐增加;种子的超氧阴离子(O-·2)产生速率先增高后降低,过氧化氢(H2O2)含量逐渐增加,脂氧合酶(LOX)活性和丙二醛(MDA)含量下降,种子浸出液相对电导率增加;种子超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性随老化处理时间的延长逐渐下降,抗坏血酸过氧化物酶(APX)和谷胱甘肽过氧化物酶(GPX)活性在老化处理初期(老化3 d前)均增加,APX活性随后降低,GPX活性无显著变化;种子抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量在老化处理1 d后即显著降低并持续保持较低水平.研究表明,不结球白菜种子在人工加速老化过程中其抗氧化系统代谢紊乱并造成活性氧累积伤害,这可能是引起不结球白菜种子老化的重要原因.