Co-culture (Miscanthus x giganteus and Pelargonium x hortorum) phytoremediation of lead-contaminated soil, impact of this trace metal on plant physiology.

The industrial past of most regions in Lorraine and the intensification of activities onsoils has increased the number of polluted sites. To rehabilitate these areas, several methods can be employed. The use of ornamental plants has been little studied, even if these species can be used to rehabilitate a site while improving its aesthetics. In this study, co-culture of Miscanthus x giganteus (MxG) and Pelargonium x hortorum (PxH) was used to clean up a soil mainly contaminated by Pb and trace metals. At the end of the experiment, lead concentrations were measured in the soil and plants. Furthermore, auxins, jasmonic acid, and salicylic acid were also measured to evaluate the defense mechanisms of the plants in front of pollutants. The results showed a reduction in lead concentrations following the phytoremediation process implemented and that PxH was able to extract lead from the soil. Results showed that co-culture was beneficial to the development of MxG. Concerning the molecules synthesized by the plants under stress conditions, only salicin was found in MxG roots and leaves in particular for plants grown in individual culture. According to the results obtained, it seems that co-culture can improve soil quality without their development being affected.