Plant responses to metal toxicity

Metal toxicity for living organisms involves oxidative and/or genotoxic mec hanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathi on-derived peptides named phytochelatins, participate in excess metal stora ge and detoxification. Low molecular weight organic molecules, mainly organ ic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative s tress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occur rence of naturally tolerant plants which hyperaccumulate metals provides he lpful tools for this research. ((C) Academie des sciences / Elsevier, Paris .).