Cellular mechanisms for heavy metal detoxification and tolerance.
Heavy metals such as Cu and Zn are essential for normal plant growth, although elevated concentrations of both essential and non-essential metals can result in growth inhibition and toxicity symptoms. Plants possess a range of potential cellular mechanisms that may be involved in the detoxification of heavy metals and thus tolerance to metal stress. These include roles for the following: for mycorrhiza and for binding to cell wall and extracellular exudates; for reduced uptake or efflux pumping of metals at the plasma membrane; for chelation of metals in the cytosol by peptides such as phytochelatins; for the repair of stress-damaged proteins; and for the compartmentation of metals in the vacuole by tonoplast-located transporters. This review provides a broad overview of the evidence for an involvement of each mechanism in heavy metal detoxification and tolerance.
Hall
J L
JL
School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Southampton SO16 7PX, UK. jlh3@soton.ac.uk
D000222:Adaptation, Physiological; D002473:Cell Wall / Q000378:metabolism; D002614:Chelating Agents / Q000378:metabolism*; D005978:Glutathione; D006360:Heat-Shock Proteins / Q000378:metabolism; D008658:Inactivation, Metabolic; D008667:Metalloproteins / Q000378:metabolism*; D008668:Metallothionein / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism* / Q000493:pharmacokinetics; D054811:Phytochelatins; D018517:Plant Roots / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
D002614:Chelating Agents; D006360:Heat-Shock Proteins; D008667:Metalloproteins; D019216:Metals, Heavy; D008668:Metallothionein; D054811:Phytochelatins; D005978:Glutathione