Metal hyperaccumulators

However, some plants can accumulate more than 0.1% of Pb, Co, Cr, and more than 1% of Mn, Ni and Zn in the shoots. These accumulator plants are called hyperaccumulators. To date, there are approximately 400 known metal hyperaccumulator plants in the world (Baker and Walker, 1989). Thlaspi caerulescens, Alyssum murale, A. lesbiacum, A. tenium are Zn and Cd hyperaccumulators. Brassica juncea, a high-biomass plant, can accumulate Pb, Cr(III), Cd, Cu, Ni, Zn, Sr, B and Se. Thlaspi caerulescens accumulates Ni. Hybrid poplar trees are reported to phytoremediate Cd and As contaminated soils. A Chinese brake fem, Pteris vittata, is an As hyperaccumulator (Ma et al., 2001). 

Salt D.E., Kramer U. Mechanisms of metal hyperaccumulation in plants. In Phytoremediation of Toxic Metals Using Plants to Clean Up the Environment, I. Raskin, B.D. Ensley, eds. New York, NY John Wiley Sons, Inc., 2000. 

Assun9ao, A. G. L., Da Costa Martins, P., De Folter, S., Vooijs, R., Schat, H., and Aarts, M. G. M., 2001, Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator Thlaspi caerulescens. Plant Cell Environ. 24 217-226. 

Weber, M., Harada, E., Vess, C., v. Roepenack-Lahaye, E., and Clemens, S., 2004, Comparative microarray analysis of Arabidopsis thaliana and Arabidopsis halleri roots identifies nicotianamine synthase, a ZIP transporter and other genes as potential metal hyperaccumulation factors. Plant J. 37 269-281. 

In June of 1999, Edenspace Systems Corporation acquired Phytotech, Inc., a company specializing in phytoremediation technologies. Phytotech has developed several proprietary techniques for the phytoremediation of sites contaminated with heavy metals and radionuclides. Phytoremediation is an emerging bioremediation technology that uses plants to remediate contaminated media. Hyperaccumulation is a specific type of phytoremediation that can be used at sites contaminated by radionuclides and heavy metals. Hyperaccumulation may be defined as the ability... 

The search for the exact sites of ion and compound deposition in plants and the nature of the chemical species involved has been carried out with a number of aims The elucidation of various mechanisms of phytochemical importance mineral uptake and utilisation toxicity and tolerance exhibited by many individual species and the study of plants that accumulate or hyperaccumulate metals. The literature for a number of individual elements to the late 1970s has been reviewed (Farago, 1981) and the phytochemistry of metal hyperaccumulators has been reviewed by Baker and Brooks (1989). 

Yang, X., Feng, Y, He, Z., and Stoffella, P.J. 2005. Molecular mechanisms of heavy metal hyperaccumulation and phytoremediation. Journal of Trace Elements in Medicine and Biology, 18(4) 339-53. 

Y He, Z., and Stoffells, P.J., Molecular mechanisms of heavy metal hyperaccumulation and phytoremediation, J. Trace Elem. Med. Biol. 18, 339-353, 2005 Mackenzie, S.A., Plant organellar protein targeting a traffic plan still under construction. Trends Cell Biol. 15, 548-554, 2005 Thompson, M.V., Phloem the long and the short of it. Trends Plant Sci. 11, 26-32, 2006 Takahashi, H., Yoshimoto, N., and Saito, K., Anionic nutrient transport in plants the molecular basis of the sulfate transporter gene family. Genet. Eng. 27, 67-80, 2006. 

Pollard AJ, Powell KD, Harper FA, Andrew J, Smith C. (2002). The genetic basis of metal hyperaccumulation in plants. Critical Reviews in Plant Sciences 21(6) 539-566. 

Prasad MNV, Freitas H. (2003). Metal hyperaccumulation in plants— Biodiversity prospecting for phytoremediation technology. Electronic Journal of Biotechnology 6 275-321. 

Baker AIM, McGrath SP, Reeves RD, Smith JAC (2000) Metal hyperaccumulator plants a review of the ecology and physiology of a biological resource for phytoremediation of metal polluted soils. In Terry N, Banuelos GS (eds) Phytoremediation of contaminated soil and water. CRC Press, Boca Raton, pp 85-107... 

In recent years, much progress has been made in identifying genes involved in metal transport. Thus it has been found that metal hyperaccumulation is mediated, at least in part, by an up to 200 times higher expression of metal transporter genes in... 

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