[Advances in the research of soil microorganisms and their mediated processes under heavy metal stress]

Abstract

More and more evidence from both laboratory and field experiments suggested that soil microbes were more sensitive to heavy metal stress than soil animals or plants living in the same soil. This understanding has been gradually accepted as a common point in this field. The history and the latest advances in soil microorganisms and its mediated processes under heavy metal stresses in soils were reviewed in this paper. It is difficult to do any comparison among the results from laboratory, field toxicological experiment and environmental monitoring. So far, a relevantly 'accurate' control soil was rarely available in the environmental monitoring. Much of evidence has indicated that not only microbial population/biomass was changed under heavy metal stress, but also its structure was varied. Although many molecular methods, such as PLFA, BIOLOG and DNA, have been developed to detect this microbial structural change, they always need many expensive instruments and accessories, and only could be done in laboratory. Therefore, some rapid and easy methods are expected to develop to substitute the traditional plate count. The speciation in the solution phase, ion effect and rhizospheric effect of heavy metal on the toxicity to soil microorganisms and its mediated processes need extent studies and discussion. Finally, the microbial indicator system of assessing heavy metal toxicity to soil microorganisms and its mediated processes need to be established.