摘要
采用盆栽试验研究了土壤外源Cd、Zn复合污染对小麦根系植物络合素(PCs)和谷胱甘肽(GSH)合成的影响。结果显示,土壤外源较高浓度Cd(3￣27mg·kg-1)抑制了小麦的生长,而单Zn处理(80￣720mg·kg-1)对其生长无影响,Cd+Zn复合处理减缓了Cd的毒性,但Zn的缓解作用有限;单Zn处理小麦根内未检出PCs,仅检出GSH,但GSH并没有随Zn浓度的增加而增加。随Cd处理浓度(≥1mg·kg-1)的增加,小麦根内PCs和GSH的含量显著增加,Cd+Zn复合处理降低了小麦根内PCs和GSH的合成水平,并随Zn浓度的增加降低作用更趋明显。回归分析显示,Cd及Cd+Zn复合污染下小麦根内PCs和GSH的含量与小麦地上部生物量的抑制率保持相当好的线性关系。结果表明,PCs和GSH对Cd的暴露表现出很强的专一性,可用于指示土壤环境中Cd及Cd和Zn复合污染的毒性。
Phytochelatins （PCs）and glutathione （GSH）have been proposed as biomarkers for the assessment of metal toxicity. However, most studies have generally been confined to one metal exposure in hydroponics. In the present study, pot experiment was conducted to investigate the synthesis of PCs and GSH in roots of wheat（ Triticum aestivum L. ）under combined pollution of Cd and Zn. The results showed that higher concentrations of Cd added（3-27 mg·kg^-1 ）in soils showed toxicity and inhibited the growth of wheat, whereas single Zn treatments（80-720 mg·kg^-1 ）in soils had no effects on it. Zn addition under the single Cd-treated soils partly alleviated Cd toxicity, accompanied by the gradual increase of shoot biomass. High performance liquid chromatography fluorescence analysis clearly showed that GSH rather than PCs was detected in roots under the single Zn-treated soils, and yet did not increase with the increase of Zn concentrations added in soils. By contrast, PCs and GSH were significantly induced in roots under the single Cd-treated soils （ ≥ 1 mg·kg^-1）and increased with the increase of Cd concentrations added in soils. Zn addition under the single Cd-treated soils decreased the levels of PCs and GSH in roots. There existed positively linear relationships between PCs concentrations, GSH concentrations in roots and inhibition rate of shoot biomass under both single Cd and combined treatments of Cd and Zn. This work further confirmed that PCs and GSH were highly sensitive to Cd exposure, and could be used as biomarkers for an evaluation of the toxicity of Cd or Cd and Zn combined pollution in soils.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2008年第5期1913-1918,共6页
Journal of Agro-Environment Science
基金
河海大学引进人才创新基金(2006402911)
河海大学浅水湖泊综合治理与资源开发教育部重点实验室开放研究基金(2006KJ007)
关键词
重金属
镉
锌
复合污染
小麦
植物络合素
谷胱甘肽
heavy metal
cadmium
zinc
combined pollution
Triticum aestivum L.
phytochelatins
glutathione
作者简介
孙琴（1976-），女，博士，主要从事重金属污染物的生物可利用性与微观毒害机理研究。E-mail：sunqinnj@hhu．edu．cn
