This indicates copper probably affected plants’ roots and rhizomes development. Total biomass weight of field plants (in a cube of similar dimensions to the ones placed in vessels) was slightly lower (ca. 13% lower, although not significantly)than in control vessels, indicating some biomass was produced during the 2 months of experiment. In fact, although roots biomass was identical between field and control plants, aerial structures biomass increased ca. 25% during the experimental period(results not shown).