利用美洲商陆修复锰尾渣污染土壤对后茬植物的影响

Effect of Phytoremediation of Manganese Mine Tailings Contaminated Soils by Phytolacca americana on Following Plants

采用盆栽法研究用锰超富集植物美洲商陆（Phytolacca americana）修复锰尾渣污染土壤对后茬植物大豆（Glycine max）和绿豆（Phaseolus radiatus）的影响。经美洲商陆修复锰尾渣污染土壤后，后茬植物大豆和绿豆的镉、铅、锌和锰含量降低，污染土壤的毒性减弱，有利于这2种植物生长。经美洲商陆修复2～3a，可显著减弱污染土壤对大豆的毒性。由此可见，在经美洲商陆修复的污染土壤上栽培大豆，可以增加含氮量，促进其他植物生长，从而维持锰尾渣污染区植被持续发展。

Removing heavy metals or reducing metal concentrations in heavy metal-contaminated soils by hyperaeeumulating plants has been proposed as one of the most promising green remediation techniques. Effects of phytoremediation of heavy metal-contaminated soils on following plants have rarely been investigated. A pot experiment was carried out to investigate effects of phytoremediation by manganese hyperaccumulating plants, Phytolacca americana, on phytotoxieity of a manganese mine tailings contaminated soil and metal accumulation of following plants Glycine max and Phaseolus radiatus therein. The soil in pots was planted first with P. americana seedlings, which were removed after one, two or three years and recorded as T- 1, T-2, and T-3, respectively. The soil not planted with P. americana served as control. Then seeds of G. max and P. radiatus were sown into those pots. Phytotoxicity of the soil in the pots treated with P. americana became lower compared with that of the control. Phytoremediation of the contaminated soils decreased concentrations of Cd, Ph, Zn and Mn in the biomass of the two plants, G. max and P. radiatus, which promoted their growth. Phytotoxicity of the soil in the pots treated with P. americana was lower to G. max than to P. radiatus. In order to maintain a long-term sustainable vegetation on lands contaminated by manganese mine railings, herbaceous legume such as G. max can be used to solve the problem of nitrogen deficiency in soils following 2-3 years of phytorcmediation with P. americana.