低分子有机酸对油菜吸收Cd和Zn的影响

本文探讨土壤中外加混合低分子有机酸(甲酸、乙酸、苹果酸、柠檬酸)对油菜吸收土壤中重金属元素Zn和Cd的影响。结果表明,随着低分子有机酸添加量的增加,Zn胁迫下,油菜地上部分Zn含量先增大后减小;Cd胁迫下,油菜地上部分Cd含量的变化较为复杂,呈现先减少,后增加,再减少的趋势。有机酸添加量的增加能提高根际土壤B1和B2态中Zn和Cd的提取量(B1态Cd除外),而对非根际土壤B1和B2态Zn和Cd的提取量无显著影响。Zn或Cd胁迫下,低浓度的有机酸能起到解毒作用,提高油菜的生物量;高浓度的有机酸能提高根际土壤B1和B2态Zn或Cd的含量,Zn或Cd的毒性增加,油菜的生长受抑制。

Effect of Low Molecular Weight Organic Acids on Cd and Zn Absorption of Rape

The effects of mixed low-molecular-weight-organic-acids(LMWOAs,acetic acid,formic acid,malic acid and citric acid) on the absorption of Cd and Zn of rape were studied in contaminated soil through pot experiments.The results showed that with the increasing amount of LMWOAs,the amounts of Cd and Zn in rape shoot exhibited complex changes.LMWOAs could increase the amounts of Cd and Zn in B1 and B2 fractions of rhizosphere soil(except Cd in B1 fractions),however,LMWOAs had little effect on Cd and Zn in nonrhizosphere soils.Under the stress condition of Cd or Zn,low concentration of LMWOAs could decrease the toxicity of Cd or Zn and increase the biomass of rape.However,high concentration of LMWOAs could increase the amount of Cd or Zn in B1 and B2 fractions of rhizosphere soil,increase the toxicity of Cd or Zn,so as to restrain the growth of rape.