摘要
测定了Hg2+、Cd2+、Cu2+、Pb2+单一重金属胁迫对拟南芥种子发芽和幼苗生长的影响.结果表明,重金属对幼苗生长的毒性大于对种子发芽的毒性,以抑制种子发芽的IC50为指标,4种重金属的毒性顺序为Hg2+>Cd2+>Pb2+/Cu2+,以幼苗生长为指标,则毒性顺序为:Cu2+>Hg2+>Cd2+/Pb2+,并随着胁迫时间延长,种子萌发率下降.此外,不同重金属在不同发芽时段对种子的毒性也不尽相同,Cd2+的毒性在种子吸水后的0～12h大于12～24h,而Hg2+毒性在12～24h大于0～12h,其中,种皮对减轻重金属毒性起着十分重要的作用.通过非毒性离子(Ca2+、Mg2+、K+、Na+)与重金属离子(Hg2+、Cd2+、Cu2+、Pb2+)交互作用对拟南芥种子发芽及幼苗生长效应的研究发现,5mmol·L-1的Ca2+、Mg2+、K+、Na+可以增强Hg2+对种子发芽的毒性,但对Cd2+的毒性却没有影响.对于幼苗来说,Ca2+、Mg2+、K+、Na+可以显著增强Hg2+的毒性,Ca2+可以缓解Cd2+的毒性,但却增加Cu2+的毒性,K+可以缓解Pb2+对幼苗的毒害作用.最后,本文对重金属的毒害机理进行了探讨.
The study on the toxicity of heavy metals Hg^2＋, Cd^2＋, Cu^2＋ and Pb^2＋ to Arabidopsis seed germination and seedling growth showed that the test heavy metals had a stronger toxicity on seedling growth than on seed germination. The toxicity on seedlings was in order of Cu^2＋〉 Hg^2＋〉 Cd^2＋ / Pb^2＋ , while on seeds was Hg^2＋〉 Cd^2＋〉 Pb^2＋/Cu^2＋. Seed germination rate was decreased with increasing stress duration, and different heavy metals showed different toxicity at different stress duration. For example, Hg^2＋ displayed a stronger toxicity at 12-24 h stress, while Cd^2＋ was at 0-12 h stress. It seemed that seed coat played an important role in seed tolerance to heavy metals. The interaction between non-toxic ions and heavy metal ions on seed germination showed that Ca^2＋, Mg^2＋, K^＋ and Na^＋ at 5 mmol· L^-1could enhance the toxicity of Hg^2＋, but did not affect Cd^2＋ toxicity. For seedling growth, Ca^2＋, Mg^2＋, K^＋ and Na^＋ might enhance the toxicity of Hg^2＋ , Ca^2＋ might alleviate the toxicity of Cd^2＋ but enhance the toxicity of Cu^2＋, and K^＋ might alleviate Pb^2＋ toxicity. The mechanism of heavy metals injury was discussed in the paper.
出处
《应用生态学报》
CAS
CSCD
北大核心
2005年第10期1943-1947,共5页
Chinese Journal of Applied Ecology
基金
中国科学院知识创新工程项目(KZCX2405)
中国科学院"十五"农业资助项目(NKA03).
关键词
种子发芽
幼苗生长
拟南芥
Seed germination, Seedling growth, Arabidopsis.
