Microbe assisted phytoremediation of heavy metal contaminated soil by using African marigold (Tagetes erecta L.)

Phytoremediation is a clean and green potentially cost-effective technology for remediating heavy metal-contaminated soil. In this study, a pot experiment was set up in which ornamental Tagetes erecta L. was grown in the pots with three concentrations i.e., 0, 5, and 10 % of contaminated soil amended with compost (2 %) in all pots of the experiment following three treatments of bacteria i.e., Co, Stutzerimonas stutzeri and Pseudomonas sundara. The experiment was composed of three replicates. After sixty days of the experiment, the plants were harvested. After harvesting morphological, physiological, antioxidants, and pollution parameters were investigated. By the inoculation of the S. stutzeri and P. sundara the height and biomass of the T. erecta enhanced as compared to control. Inoculated bacteria S. stutzeri and P. sundara enhanced the pigments, protein and water content of the plants. Bacteria also enhanced the antioxidants e.g., melatonin, catalase, peroxidase, ascorbate peroxidase and proline to minimize oxidative stress as evidenced by the reduction of hydrogen peroxide. The plants treated with S. stutzeri and P. sundara absorb high concentrations of heavy metals (chromium, cadmium and lead) in their parts. Post-analysis of the soil showed a decrease in pollution indicators. The results of this study can be used for the management and decontamination of the heavy metal polluted sites with the help of hyperaccumulator ornamental plants by inoculation of bacteria.