Metal-Resistant Microorganisms and Metal Chelators Synergistically Enhance the Phytoremediation Efficiency of Solanum nigrum L. in Cd- and Pb-Contaminated Soil

摘要

The effects of metal-resistant microorganisms and metal chelators on the ability of Solanum nigrumL. to accumulate heavy metals were investigated. In the presence of multiple metal contaminants (Cd and Pb),citric acid (CA) significantly enhanced the biomass and Cd accumulation of S. nigrum, but these conditionsdecreased the accumulation of Pb. Application of Cd-or Pb-resistant microorganisms improved the ability of S.nigrum to accumulate heavy metals and increased plant yield, but the effects of microorganisms onphytoextraction were smaller than the effects of CA. When plants were grown in the presence of Cdcontamination, the co-application of CA and metal-resistant strains enhanced biomass by 30-50%andincreased Cd accumulation by 25-35%. However, these conditions decreased Pb accumulation in the presenceof Pb pollution. S. nigrum could tolerate a combination of Cd and Pb pollution. In the presence of CA and themetal-resistant microorganisms, the plants were able to acquire 15-25%more Cd and 10-15%more Pb thancontrol plants. We propose that the synergistic combination of plants, microorganisms and chelators canenhance phytoremediation efficiency in the presence of multiple metal contaminants.