Optimization of Plant-Bacteria Complex for Phytoremediation of Contaminated Soils

摘要

The aim of the present study is to optimize the plant-microbe combinations to clean up multi-metal contaminated soils. Three different Bacillus bacteria strains were introduced into the rhizosphre of the Indian mustard plant growing in soil contaminated with mixture of selenium (Se), cadmium (Cd) and chromium (Cr). The experimental design , Plackett-Burman has been used to optimize a novel crosslinked trace metals -rhizosphere bacteria complex as a potential system for phytoremediation of contaminated soils. Three bacterial strains were isolated from highly contaminated sediments with different trace and heavy metals and introduced into the rhizosphere of Indian mustard ( Brassica juncea L.) in soil contaminated with mixture of selenium (Se), cadmium (Cd) and chromium (Cr) to study the plant-microbe interactions on metal removal. The results showed that inoculating high-density of B. licheniformis in the rhizosphere of Indian mustard was enhanced Cd accumulation in plant tissues. High densities of all examined bacteria were assisting on removal of Cr from the soil whereas; Se accumulation was achieved in association with low bacterial densities in the rhizosphere. This study shows that the rhizosphere bacteria are metal-specific, in addition the bacteria isolated from certain contaminated sites may be used in conjunction with other plant species to improve their phytoremediation potential.