Growing Development and Physiological Characteristics of Seeds Harvested Different Days after Pollination and Their 7-day Seedlings of Two Yellow-Seeded Cultivars of Brassica napus L.

两个黄籽油菜品种授粉后不同时期种子及其萌发后幼苗的生长发育和生理特性研究

This study aimed to understand the growing development and physiological characteristics of seeds harvested different days after pollination and the seedlings emerged from the seeds of yellow-seeded Brassica napus L..Two yellow-seeded cultivars‘Hongyuan 558’and‘Qinyou 806’were selected in this study,and 50 seeds were collected 30,35,and 40 d after pollination,respectively.The seeds were weighed and placed on filter paper for hydroponic experiments.The seed germination rate was determined 3-5 d later.The physiological indicators including superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)activities and malondialdehyde(MDA)content were measured for the seeds harvested different days after pollination and the 7-day-seedlings emerged from the seeds.The results showed that the seed dry weights and germination rates of both‘Qinyou 806’and‘Hongyuan 558’increased as the days after pollination increased,especially 30-35 d after pollination.The germination rate and dry and fresh weights of the seeds showed no significant differences between the two cultivars,and almost all the seeds germinated 40 d after pollination.As the days after pollination increased,the SOD activities in the seeds of both cultivars first increased and then decreased,reaching their peaks 35 d after pollination,which may be related to encountering adverse stress.The POD activity in the seeds of‘Qinyou 806’kept declining,and that of‘Hongyuan 558’first increased and then decreased,which may be related to the antioxidant mechanism and adaptive regulation.The CAT activities in the seeds of both cultivars first decreased and then increased.The MDA content in the seeds of‘Qinyou 806’first decreased and then increased,while that of‘Hongyuan 558’kept reducing and was the highest in the seeds 30 d after pollination,which indicated‘Hongyuan 558’was mildly affected by the environment and had strong resistance.The activities of SOD and POD in the seedlings of two cultivars that were emerged from the seeds 35-40 d after pollination became weakened,which may be related to their exposure to stress.The CAT activity in the seedlings of‘Hongyuan 558’was generally higher than that of‘Qinyou 806’,indicating that‘Hongyuan 558’had stronger stress resistance.The MDA content in the seedlings emerged from the seeds 35-40 d after pollination showed a decreasing trend,indicating that the seedlings emerged from the seeds harvested at this stage had mild cell membrane damage and enhanced stress resistance.In conclusion,‘Hongyuan 558’had strong environmental adaptability and stress resistance.

为了解黄籽油菜在授粉后不同时期种子及其萌发后幼苗的生长状况和生理特性,该研究以‘鸿源558’和‘秦优806’为材料,分别取授粉后30、35和40d的种子各50粒,称量其干湿重并置于滤纸上做水培试验,3~5d后统计种子发芽率,7 d后选取30株幼苗和不同时期种子进行SOD、POD、CAT活性和MDA含量的测定。结果显示,‘秦优806’和‘鸿源558’两个品种的种子干重与发芽率呈现持续增长趋势且授粉后30~35 d增长更明显,两黄籽油菜品种的发芽率和干鲜重无显著差异,授粉后40 d种子发芽率接近100%。‘秦优806’和‘鸿源558’种子的SOD活性随着收获时间的延长呈现先上升后下降的趋势,皆于授粉后35 d达到峰值,这可能与遇到逆境胁迫有关;‘秦优806’种子POD活性持续下降,而‘鸿源558’先上升后下降,这可能与种子的抗氧化防御机制与适应调节能力有关;两品种种子的CAT活性随着收获时间的延长先下降后上升;‘秦优806’种子中MDA含量变化趋势为先下降后上升,而‘鸿源558’则持续下降,在授粉后30 d种子中MDA含量均较高,说明‘鸿源558’受环境影响较小,抗性较强。两品种幼苗在授粉后35~40 d SOD和POD活性均呈下降趋势,这可能与其受到逆境胁迫有关;‘鸿源558’幼苗的CAT活性高于‘秦优806’,说明‘鸿源558’抗逆性更强;授粉后35~40d,两品种MDA含量皆呈下降趋势,表明此阶段幼苗细胞膜损伤程度小,抗性不断增强。综上所述,‘鸿源558’环境适应性更强,抗逆性更好。