关键词: 南方苋, 镉胁迫, 种子萌发, 生理特性, 转运系数, 富集系数

Abstract: In order to investigate the adaptability and physiological characteristics of Amaranthus australis to Cd stress during germination and seedling stage,the effects of different Cd concentration (0,10,20,40 mg·kg^-1) on the seed germination,seedling growth and physiology were studied. Results showed that Cd stress had less effect on the seed germination rate,germination potential and germination index,but significantly reduced vigor index. The growth significantly declined along with the increasing Cd concentration,as indicated by the reduced length of radicle and germ,plant height as well as the declined dry biomass of above- and underground part,whereas had no significant changes in the radicle/germ ratio and root/shoot ratio. The leaf electrolyte leakage and malondialdehyde (MDA) content significantly increased and catalase (CAT) activity decreased with increasing the Cd concentration,while the superoxide dismutase (SOD) and peroxidase (POD) activity increased at the initial treatment and then decreased. The content of non-protein thiols (NPTs),phytochelatins (PCs),glutathione (GSH),above and underground part Cd content,translocation factor and bioaccumulation factor significantly enhanced with increasing the Cd concentration. Those results indicated that the increased NPTs,PCs and GSH contributed to the better Cd stress tolerance and the capability of Cd translocation and bioaccumulation in Amaranthus australis.

Key words: Amaranthus australis, Cadmium stress, Seed germination, Physiological characteristics, Translocation factor, Bioaccumulation factor