Stress reduction with co-culture of <i>Miscanthus x giganteus</i> and <i>Pelargonium x hortorum</i> in a pb contaminated soil to improve biomass production

The industrial past of most regions in Lorraine and the intensification of activities on soils has increased the number of polluted sites. To rehabilitate these areas, several methods can be employed. In this study, co-culture of Miscanthus x giganteus and Pelargonium x hortorum was used to clean up a soil mainly contaminated by metallic elements including lead. The use of ornamental plants has been little studied, even if these species can be used to rehabilitate a site while improving its esthetics. At the end of the experiment, Pb concentrations were measured in the soil and plants. Furthermore, phytohormones were also measured to evaluate the defense mechanisms of the plants in front of pollutants. The results showed a reduction in Pb concentrations following the phytoremediation process implemented and that PxH was able to extract Pb from the soil. Results showed that co-culture was not beneficial to the development of MxG. Concerning the molecules synthesized by the plants under stress conditions, only salicin was found in MxG roots and aerial parts in particular for plants grown in individual culture. According to the results obtained, it seems that MxG is able to make compromises between the synthesis of protective molecules and its development.