Metal hyperaccumulation: advantage for both the plant and the human being?

Abstract

Metal hyperaccumulation: advantage for both the plant and the human being?

Metal hyperaccumulation is the ability of some plants to accumulate metals in their tissues to levels above normal concentrations without any toxicity symptoms. Hyperaccumulating plants have evolved internal tolerance mechanisms to metal toxicity. This peculiarity makes them very useful for us as a tool for new phytoremediation technologies. Nevertheless, which is the benefit of metal hyperaccumulation for the plant itself? Different hypothesis have been proposed but the most remarkable is an adaptive advantage of these plants against biotic stress. This proposal is one of the most attractive to account for the "reason to be" of these metal hyperaccumulating species. In this paper two essential aspects are pointed out: the tolerance mechanisms of metal accumulation in these plants and whether metal hyperaccumulation is really an adaptive advantage.