Phytoremediation of heavy metals from industrially contaminated soil using sunflower (Helianthus annus L.) by inoculation of two indigenous bacteria

The phytoremediation technique is gaining excessive consideration as a promising method to remediate indus-trially contaminated soils with heavy metals. In this study, a pot experiment was performed in which the ornamental plant Helianthus annus 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. After sixty days of the experiment, the plants were harvested and morphological, physiological, antioxidants and pollution parameters were investigated. The plant height and biomass of the sunflower were increased by the inoculation of S. stutzeri and P. sundara. Pig-ments e.g., chlorophyll a, b, carotenoids and proteins of the plants were enhanced. There was an increase in antioxidants e.g., catalase, peroxidase, ascorbate peroxidase and proline content and a decrease in hydrogen peroxide content of plants by inoculation of S. stutzeri and P. sundara. The bacteria boosted the uptake of heavy metals (cadmium, chromium and lead) in parts of plants. Post-harvested soil analysis indicated decreased electronic conductivity, total dissolved solids, bicarbonates and heavy metals in the soil. In the future, the combination of H. annus and bacteria could be a better technique to remediate the heavy metals in industrially polluted soils.