Seminario: Cannabis sativa to remediate copper-polluted soils

Phytoremediation employs the ability of some plants to absorbe and accumulate heavy metals from contaminated soils and waters. Generally, plants for phytoremediation are annual herbs with a low or null economic value and very little biomass. The goal is to combine phytoremediation with crops of high biomass or of commercial interest. Cannabis sativa could be one of the candidates for its high biomass, and because it is not involved in the food chain. We examined the ability of Cannabis sativa to take up and tolerate Cu salts from a nutrient solution. By means of electron microscopy and X-ray microanalysis, we observed Cu accumulation in upper leaf epidermal cells, in spiculae and in abaxial trichomes. No traces of this metal was found in epidermal cells of the stem. Even if Cannabis seems not to have evolved a specific tolerance and accumulation mechanisms, it shows to have a considerable potential for phytoremediation purposes. It is able to transfer Cu from the root to the shoot, one of the criteria that must be met to consider a plant well suited for phytoremediation. Moreover the fibres seem not to be affected by Cu contamination, allowing them to be collected and used with economical advantage.