菌根植物根际环境对污染土壤中Cu、Zn、Pb、Cd形态的影响

采用根垫法和连续形态分析技术，分析了生长在污灌土壤中菌根小麦和无菌根小麦根际Ｃｕ、Ｚｎ、Ｐｂ、Ｃｄ的形态分布和变化趋势。结果表明，下对照土壤相比，菌根际土壤中交换态Ｃｕ含量显著增加，交换态Ｃｄ呈减少的趋势；与非菌根际相比，Ｃｕ、Ｚｎ、Ｐｂ的有机结合态在菌根根际中显著增加，而４种测定金属２的碳酸盐态和铁锰氧化态都没有显著改变，该结果表明，植物根系能影响根际中金属形态的变化，且菌根比无菌根的影响程度大

Effect of rhizospheric environment of VA-mycorrhizal plants on forms of Cu,Zn,Pb and Cd in polluted soil

Maize ( Zea mays L.) was inoculated with or without VA mycorrhizal ( Glomus mosseae ) and cultivated in a heavy metals contaminated soil. The distribution and dynamics of Cu,Zn,Pb and Cd forms in rhizosphere of maize inoculated with or without VA mycorrhizal were analyzed with the technique of sequential extraction. Comparing with control soil, exchangeable Cu in rhizospheric soil increased significantly, and the exchangeable Cd trended down. In rhizosphere of VA mycorrhizal maize, the amounts of Cu, Zn and Pb bound to organic matter were significantly higher than those in rhizosphere of non mycorrhizal maize, while the four tested metals bound to carbonates and to iron and manganese oxides were constant in rhizosphere of mycorrhizal and non mycorrhizal maize. These results illustrated that the plant roots could influence the distribution and dynamics of metal forms in rhizosphere, and much for mycorrhizal plants than for non mycorrhizal plants. At excessive concentration of soil metals, mycorrhizal roots might decrease the bio availability of toxic heavy metals by changing their forms. The factors that caused the change of metal fractions in rhizosphere of mycorrhizal and non mycorrhizal plants were also discussed.