钙离子和镁离子对小白菜铜急性毒性的影响

[目的]为了解土壤中的Cu毒性的机制及污染防控。[方法]采用单因素控制试验,单独变化Ca2+和Mg2+一种离子浓度来研究其对小白菜Cu毒性的影响。[结果]随着Ca2+和Mg2+浓度的增加,以总Cu浓度表示的小白菜根伸长的半抑制浓度(EC50CuT)线性增加2倍,而以自由Cu2+活度表示的小白菜根伸长的半抑制浓度(EC50Cu2+)没有随着Ca2+和Mg2+浓度的改变而发生显著变化。[结论]利用自由Cu2+活度可以较准确地评价Cu对小白菜的毒性。

Effects of Ca and Mg Ions on Copper Toxicity to Pakchoi

[Objective]The research aimed to understand the mechanism of copper toxicity in the soil and control and prevent the pollution.[Method] To determine the effect of different cations on Cu toxicity,the concentration of one was varied,while the concentrations of all others were kept as constant as possible.[Result] Increases in Ca2＋,Mg2＋ and H＋ significantly increased the median effective concentrations（EC50CuT,i.e.the concentration that reduced root elongation by 50% based on total soluble Cu） by a factor of 12 for all treatments,which clearly demonstrated the limitation of using total Cu concentration to predict Cu toxicity to pakchoi.EC50Cu2＋（i.e.the concentration that reduced root elongation by 50% based on free Cu2＋ activity） wasn＇t significantly influenced by changing Ca2＋,Mg2＋ and H＋ activities.[Conclusion] Free Cu2＋ activity could accurately evaluate the toxicity of copper on the pakchoi.