The Botanical Review

, Volume 75, Issue 4, pp 339–364

Phytoremediation of Heavy Metals: Physiological and Molecular Mechanisms



Heavy metals (HM) are a unique class of toxicants since they cannot be broken down to non-toxic forms. Concentration of these heavy metals has increased drastically, posing problems to health and environment, since the onset of the industrial revolution. Once the heavy metals contaminate the ecosystem, they remain a potential threat for many years. Some technologies have long been in use to remove, destroy and sequester these hazardous elements. Even though effective techniques for cleaning the contaminated soils and waters are usually expensive, labour intensive, and often disturbing. Phytoremediation, a fast-emerging new technology for removal of toxic heavy metals, is cost-effective, non-intrusive and aesthetically pleasing. It exploits the ability of selected plants to remediate pollutants from contaminated sites. Plants have inter-linked physiological and molecular mechanisms of tolerance to heavy metals. High tolerance to HM toxicity is based on a reduced metal uptake or increased internal sequestration, which is manifested by interaction between a genotype and its environment. The growing interest in molecular genetics has increased our understanding of mechanisms of HM tolerance in plants and many transgenic plants have displayed increased HM tolerance. Improvement of plants by genetic engineering, i.e., by modifying characteristics like metal uptake, transport and accumulation and plant’s tolerance to metals, opens up new possibilities of phytoremediation. This paper presents an overview of the molecular and physiological mechanisms involved in the phytoremediation process, and discusses strategies for engineering plants genetically for this purpose.

Literature Cited

  1. Assuncao, A. G. L., P. DaCosta Martins, S. Folter, R. Vooijs, H. Schat & M. G. M. Aarts. 2001. Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator Thlaspi caerulescens. Plant. Cell Environ. 24: 217–226.Google Scholar
  2. Axtell, N. R., S. P. K. Sternberg & K. Claussen. 2003. Lead and nickel removal using Microspora and Lemna minor. Biores. Technol. 89: 41–48.Google Scholar
  3. Babaoglu, M., S. Gezgin, A. Topal, B. Sade & H. Dural. 2004. Gypsophila sphaerocephala Fenzl ex Tchihat: a boron hyperaccumulator plant species that may phytoremediate soils with toxic B levels. Turk. J. Bot. 28: 273–278.Google Scholar
  4. Bachem, C. W. B., R. S. V. Hoeren, S. M. D. Bruijn, D. Vreugdenlicl, M. Zabeau & R. G. F. Visser. 1996. Visualization of differential gene expression using a novel method of RNA fingerprinting based on AFLP: analysis of gene expression during potato tuber development. Plant J. 9: 745–753.PubMedGoogle Scholar
  5. Bae, W. & R. K. Mehra. 1998. Properties of glutathione and phytochelatins-capped CdS bioanocryatallites. J. Inorg. Biochem. 69: 33–43.Google Scholar
  6. Baker, A. J. M. & P. L. Walker. 1989. Physiological responses of plants to heavy metals and the quantification of tolerance and toxicity. Chem. Spec. Bioavail. 1: 7–17.Google Scholar
  7. ———, S. P. McGrath, R. D. Reeves & J. A. C. Smith. 2000. Metal hyperaccumulator plants: a review of the ecology and physiology of a biological resource for phytoremediation of metal polluted soils. Pp 85–107. In: N. Terry & G. Banuelos (eds). Phytoremediation of contaminated soil and water. Lewis, Boca.Google Scholar
  8. ———, R. D. Reeves & A. S. M. Hajar. 1994. Heavy metal accumulation and tolerance in British population of the metallophyte Thlaspi caerulescens J & C presl (Brassicaceae). New Phytol. 127: 61–68.Google Scholar
  9. Banuelos, G. S. 2000. Phytoextraction of Se from soils irrigated with selenium-laden effluent. Plant Soil. 224: 251–258.Google Scholar
  10. ———, Z. Q. Lin, I. Arroyo & N. Terry. 2005. Selenium volatilization in vegetated agricultural drainagesediment from the San Luis Drain, Central California. Chemosphere 60: 1203–1213.PubMedGoogle Scholar
  11. Beltramini, M. & K. Lerch. 1982. Copper transfer between Neurospora copper metallothionein and type 3 copper apoproteins. FEBS Lett 142: 219–222Google Scholar
  12. Berti, W. R. & S. D. Cunningham. 2000. Phytostabilization of metals. Pp 71–88. In: I. Raskin & B. D. Ensley (eds). Phytoremediation of toxic metals: using plants to clean up the environment. Wiley, New York.Google Scholar
  13. Bizily, S. P., T. Kim, M. K. Kandasamy & R. B. Meagher. 2003. Subcellular targeting of methylmercury lyase enhances its specific activity for organic mercury detoxification in plants. Plant Physiol. 131: 463–471.PubMedGoogle Scholar
  14. Blaylock, M. J. & J. W. Huang. 2000. Phytoextraction of metals. Pp 53–69. In: I. Raskin & B. D. Ensley (eds). Phytoremediation of toxic metals: using plants to clean up the environment. Wiley, New York.Google Scholar
  15. ———, D. E. Salt, S. Dushenkov, O. Zakharova, C. Gussman, Y. Kapulnik, B. D. Ensley & I. Raskin. 1997. Enhanced accumulation of Pb in Indian mustard by soil-applied chelating agents. Environ. Sci. Tech. 31: 860–865.Google Scholar
  16. Brooks, R. R. 1998. General Introduction. Pp 1–14. In: R. R. Brooks (ed). Plants that hyperaccumulate heavy metals: their role in phytoremediation, microbiology, archaeology, mineral exploration and phytomining. CAB International, New York.Google Scholar
  17. Brouwer, M., T. Hoexum-Brouwer & R. E. Cashon. 1993. A putative glutathione-binding site in Cd Zn-metallothionein identified by equilibrium binding and molecular modeling studies. Biochem. J. 294: 219–225.PubMedGoogle Scholar
  18. Brown, S. L., R. L. Chaney, J. S. Angle & A. J. M. Baker. 1994. Phytoremediation potential of Thlaspi caerulescens and bladder compion for zinc- and cadmium contaminated soil. J. Environ. Qual. 23: 1151–1157.Google Scholar
  19. Brune, A., W. Urbach & K. J. Dietz. 1994. Compartmentation and transport of Zinc in barley primary leaves as basic mechanisms involved in Zinc tolerance. Plant Cell Environ. 17: 1581–1585.Google Scholar
  20. Bubb, J. M. & J. N. Lester. 1991. The impact of heavy metals on lowland rivers and the implications for man and the environment. Sci. Tot. Environ. 100: 207–233.Google Scholar
  21. Celestino, M. D. R., R. Font, R. M. Rojas & A. D. H. Bailon. 2006. Uptake of lead and zinc by wild plants growing in contaminated soils. Indust. Crops Prod. 24: 230–237.Google Scholar
  22. Chandrashekhar, K., C. T. Kamala, N. S. Chary, A. R. K. Sastry, T. N. Rao & M. Vairamani. 2004. Removal of lead from aqueous solutions using an immobilized biomaterial derived from a plant biomass. J. Haz. Mat. 108: 111–117.Google Scholar
  23. Chaney, R. L. 1988. Metal speciation and interactions among elements affect trace element transfer in agricultural and environmental food chains. Pp 218–260. In: J. R. Kramer & H. E. Allen (eds). Metal speciation: theory, analysis and applications. Lewis Publishers Chelsea, MI.Google Scholar
  24. Chatthai, M., K. H. Kaukinen, T. J. Tranbarger, P. K. Gupta & S. Misra. 1997. The isolation of a novel; metallothionein related cDNA expressed in somatic and zygotic embryos of Douglas fir: regulation of ABA, osmoticum and metal ions. Plant Mol. Biol. 34: 243–254.PubMedGoogle Scholar
  25. Che, D., R. B. Meagher, A. C. P. Heaton, A. Lima, C. L. Rugh & S. A. Merkle. 2003. Expression of mercuric ion reductase in eastern cottonwood (Populus deltoids) confers mercuric ion reduction and resistance. Plant Biotechnol. J. 1: 311.PubMedGoogle Scholar
  26. Chen, Q. & J. W. C. Wong. 2006. Growth of Agropyron elongatum in a stimulated nickel contaminated soil with lime stabilization. Sci. Tot. Environ. 366: 448–455.Google Scholar
  27. Cherian, S. & M. M. Oliveira. 2005. Transgenic plants in phytoremediation: recent advances and new possibilities. Environ. Sci. Technol. 39: 9377–9390.PubMedGoogle Scholar
  28. Clemens, S. 2001. Molecular mechanism of plant metal homeostasis and tolerance. Planta 212: 475–486.PubMedGoogle Scholar
  29. ———, E. J. Kim, D. Neumann & J. I. Schroeder. 1999. Tolerance to toxic metals by a gene family of phytochelatin synthases from plants and yeast. EMBO J. 18: 3325–3333.PubMedGoogle Scholar
  30. Cobbett, C. S. & P. Golsbrough. 2002. Phytochelatins and metallothioneins: roles in heavy metals detoxification and homeostasis. Ann. Rev. Plant. Biol. 53: 159–182.Google Scholar
  31. Cohen, C. K., T. C. Fox, D. F. Garvin & L. V. Kochian. 1998. The role of iron-deficiency stress responses in stimulating heavy-metal uptake transport in plants. Plant Physiol. 116: 1063–1072.PubMedGoogle Scholar
  32. Connolly, E. L., J. P. Fett & M. L. Guerinot. 2002. Expression of the IRT1 metal transporter is controlled by metals at the levels of transcript and protein accumulation. Plant Cell 4: 1347–1357.Google Scholar
  33. Cunningham, S. D., W. R. Berti & J. W. Huang. 1995. Phytoremediation of contaminated soils. Trends Biotechnol. 13: 393–397.Google Scholar
  34. Cutler, J. M. & D. M. Rains. 1974. Characterisation of Cd uptake by plant tissue. Plant Physiol. 54: 67–71.PubMedGoogle Scholar
  35. Davies, K. L., M. S. Davies & D. Francis. 1991. Zinc-induced vacoulation in root meristematic cells of Festuca rubra L. Plant Cell Environ. 14: 399–406.Google Scholar
  36. Deesouza, M. P., E. A. H. Pilon-Smits & N. Terry. 2000. The physiology and biochemistry of selenium volatilization by plants. Pp 171–190. In: I. Raskin & B. D. Ensley (eds). Phytoremediation of toxic metals: using plants to clean up the environment. Wiley, New York.Google Scholar
  37. Dela Fuente, J. M., Y. Ramirez-Rodriguez, J. L. Cabrera-Ponce & L. Herrera Estrella. 1997. Aluminium tolerance in transgenic plants by alteration of citrate synthesis. Science 276: 1566–1568.Google Scholar
  38. Dhankher, O. P., Y. Li, B. P. Rosen, J. Shi, D. Salt, J. F. Senecoff, N. A. Sashti & R. B. Meagher. 2002. Engineering tolerance and hyperaccumulation of arsenic in plants by combining arsenate reductase and g-glutamylcysteine synthetase expression. Nat. Biotechnol. 20: 1140–1145.PubMedGoogle Scholar
  39. ———, N. A. Shasti, B. P. Rosen, M. Fuhrmann & R. B. Meagher. 2003. Increased cadmium tolerance and accumulation by plants expressing bacterial arsenate reductase. New Phytol. 159: 431–441.Google Scholar
  40. Diwan, H., A. Ahmad & M. Iqbal. 2008. Genotypic variation in the phytoremediation potential of Indian mustard for chromium. Environ. Manag. 29: 473–478.Google Scholar
  41. Dushenkov, D. 2003. Trends in phytoremediation of radionucliides. Plant Soil 249: 167–175.Google Scholar
  42. ———, P. B. A. N. Kumar, H. Motto & I. Raskin. 1995. Rhizofiltration: the use of plants to remove heavy metals from aqueous streams. Environ. Sci Technol. 29: 1239–1245.Google Scholar
  43. ———, D. Vasudev, Y. Kapulnik, D. Gleba, D. Fleisher, T. C. Ting & B. Ensley. 1997. Removal of uranium from water using terrestrial plants. Environ. Sci. Technol. 12: 3468–3474.Google Scholar
  44. ——— & Y. Kapulnik. 2000. Phytofiltration of metals. Pp 89–106. In: I. Raskin & B. D. Ensley (eds). Phytoremediation of toxic metals - using plants to clean up the environment. Wiley, New York.Google Scholar
  45. ———, M. Skarzhinskaya, K. Glimelius, D. Gleba & I. Raskin. 2002. Bioengineering of a phytoremediation plant by means of somatic hybridization. Int. J. Phytorem. 4: 117–126.Google Scholar
  46. Eapen, S. & S. F. Dsouza. 2005. Prospects of genetic engineering of plants for phytoremediation of toxic metals. Biotech. Adv. 23: 97–114.Google Scholar
  47. ———, K. Suseelan, S. Tivarekar, S. Kotwal & R. Mitra. 2003. Potential for rhizofiltration of uranium using hairy root cultures of Brassica juncea and Chenopodium amaranticlor. Environ. Res. 91: 127–133.PubMedGoogle Scholar
  48. Ellis, D. R., T. G. Sors, D. G. Brunk, C. O. Albrecht, B. Lahner, K. V. Wood, H. H. Harris, I. J. Pickering & D. E. Salt. 2004. Production of S methylselenocysteine in transgenic plants expressing selenocysteine methyltransferase. BMC Plant Biol. 4: 1.PubMedGoogle Scholar
  49. Eren, E. & J. M. Arguello. 2004. ArabidopsisHMA2, a divalent heavy metal-transporting PIB –type ATPase, is involved in cytoplasmic Zn2+ homeostasis. Plant Physiol. 136: 3712–3723.PubMedGoogle Scholar
  50. Ernest, W. H. O. 1996. Schermetalle. Pp 191–219. In: C. H. Brunold, A. Ruegsegger, & R. Braendle (eds). Stress Bei Pflanzen. Verlag Paul Haupt, Berlin.Google Scholar
  51. Evans, K. M., J. A. Gatehouse, W. P. Lindsay, J. Shi, A. M. Tommey & N. J. Robinson. 1992. Expression of the pea metallothionein-like gene PsMTA in Escherichia coli and Arabidopsis thaliana and analysis of trace metal ion accumulation: implications for PsMTA function. Plant Mol. Biol. 20: 1019–1028.PubMedGoogle Scholar
  52. Ezaki, B., R. C. Gardner, Y. Ezaki & H. Matsumoto. 2000. Expression of aluminium-induced genes in transgenic Arabidopsis plants can ameliorate aluminium stress and/or oxidative stress. Plant Physiol. 122: 657–665.PubMedGoogle Scholar
  53. Forstner, U. 1995. Land contamination by metals: global scope and magnitude of the problem. Pp 1–33. In: H. E. Allen, C. P. Huang, G. W. Bailey, & A. R. Bowers (eds). Metal speciation and contamination of soil. CRC, Boca Raton.Google Scholar
  54. Garcia-Hernandez, M., A. Murphy & L. Taiz. 1998. Metallothioneins 1 & 2 have distinct but overlapping expression patterns in Arabidopsis. Plant Physiol. 118: 387–397.PubMedGoogle Scholar
  55. Ghosh, M., J. Shen & B. P. Rosen. 1996. Pathways of As (III) detoxification in Saccharomyces cerevisae. Proc. Nat. Acad. Sci. USA 196: 5001–5006.Google Scholar
  56. ——— & S. P. Singh. 2005. A review on phytoremediation of heavy metals and utilization of its by-products. Appl. Ecol. Envrion. Res. 3: 1–18.Google Scholar
  57. Gisbert, C., R. Ros, A. de Haro, D. J. Walker, M. P. Bernal, R. Serrano & J. Navarro-Avino. 2003. A plant genetically modified that accumulates Pb is especially promising for phytoremediation. Biochem. Biophys. Res. Comm. 303: 440–445.PubMedGoogle Scholar
  58. Gleba, D., N. V. Borisjuk, L. G. Borisjuk, R. Kneer, A. Poulev, M. Skarzhinskaya, S. Dushenkov, S. Logendra, Y. Y. Gleba & I. Raskin. 1999. Use of plant roots for phytoremediation and molecular farming Proc. Nat. Acad. Sci. 96: 5973–5977.Google Scholar
  59. Gonzaga, M. I. S., J. A. G. Santos & L. Q. Ma. 2006. Arsenic chemistry in the rhizosphere of Pteris vittata L. and Nephrolepis exaltata L. Environ. Pollut. 143: 254–260.Google Scholar
  60. Goto, F., T. Yoshihara, N. Shigemoto, S. Toki & F. Takaiwa. 1999. Iron fortification of rice seed by the ferritin gene. Nat. Biotechnol. 17: 282–286.PubMedGoogle Scholar
  61. Grill, E., S. Loffler, E. L. Winnacker & M. H. Zenk. 1989. Phytochelatins, the heavy-metal binding peptides of plants, are synthesized from glutathione by a specific gamma-glutamylcysteine dipeptidyl transpeptidase (phytochelatin synthase). Proc. Nat. Acad. Sci. 86: 6838–6842.PubMedGoogle Scholar
  62. Gueldry, O. 2003. YCF1p-dependent HG (II) detoxification in Saccharomyces cerevisiae. Eur. J. Biochem. 270: 2486–2496.PubMedGoogle Scholar
  63. Guerinot, M. L. 2000. The ZIP family of metal transporters. Biochem. Biophys. Acta 1465: 190–198.PubMedGoogle Scholar
  64. Ha, S. B., A. P. Smith, R. Howden, W. M. Dietrich, S. Bugg, M. J. O’Connell, P. B. Goldsbrough & C. S. Cobbett. 1999. Phytochelatin synthase genes from Arabidopsis and the yeast Schizosaccharomyces pombe. Plant Cell 11: 1153–1163.PubMedGoogle Scholar
  65. Halim, M., P. Conte & A. Piccolo. 2003. Potential availability of heavy metals to phytoextraction from contaminated soils induced by exogenous humic substances. Chemosphere 52: 265–275.PubMedGoogle Scholar
  66. Hall, J. L. & J. E. Williams. 2003. Transition metal transporters in plants. J. Exp. Bot. 54: 2601–2613.PubMedGoogle Scholar
  67. Hamon, R. E. & J. M. McLaughlin. 1999. Use of the hyperaccumulator Thlaspi caerulescens for bioavailable contaminant stripping. Pp 908–909. In W. W. Wenzel et al. (eds.), Proc. 5th Intern. Conf. Biogeochemistry of trace elements-ICOBTE, Vienna.Google Scholar
  68. Hannink, N., S. J. Roser, C. E. French, A. Basran, J. A. H. Murray, S. Nicklin & N. C. Bruce. 2001. Phytoremediation of TNT by transgenic plants expressing a bacterial nitroreductase. Nature Biotech 19: 1108–1172.Google Scholar
  69. Haque, N., J. R. Peralta-Videa, G. L. Jones, T. E. Gill & J. L. Gardea-Torresdey. 2007. Screening the phytoremediation potential of desert broom(Baccharis sarothroides Gray) growing on mine trailings in Arizona, USA. Environ. Pollut. 1–7.Google Scholar
  70. Hardiman, R. T., B. Jacoby & A. Banin. 1984. Factors affecting the distribution of cadmium, copper and lead and their effects upon yield and zinc content in bush bean (Phaseolus vulgaris L.). Plant Soil 81: 17–27.Google Scholar
  71. Hart, J. J., R. M. Welch, W. A. Norvell, L. A. Sullivan & L. V. Kochi. 1998. Characterization of Cadmium binding uptake and translocation in intact seedlings of bread and durum wheat cultivars. Plant Physiol. 116: 1413–1420.PubMedGoogle Scholar
  72. Hesegawa, I., E. Terada, M. Sunairi, H. Wakita, F. Shinmachi, A. Noguchi, M. Nakajima & J. Yazaki. 1997. Genetic improvement of heavy metal tolerance in plants by transfer of the yeast metallothionein gene (CUP1). Plant Soil 196: 277–281.Google Scholar
  73. Higuchi, K., K. Suzuki, H. Nakanishi, H. Yamaguchi, N. K. Nishizawa & S. Mori. 1999. Cloning of nicotinamide synthase genes, novel genes involoved in the biosynthesis of phytosiderophores. Plant Physiol. 119: 471–479.PubMedGoogle Scholar
  74. Hooda, V. 2007. Phytoremediation of toxic metals from soil and wastewater. J. Environ. Biol. 28: 367–376.PubMedGoogle Scholar
  75. Horst, W. J., M. K. Schenk, A. N. Bürkert, H. Claassen, W. B. Flessa, H. Frommer, H. Goldbach, W. Olfs, V. Römheld, B. Sattelmacher, U. Schmidhalter, S. Schubert, N. V. Wirén & L. Wittenmayer. 2002. Influence of membrane surface charge on nutrient uptake in plants. Pp 198–199. In: R. J. Reid, Q. Zhang, & H. Sekimoto (eds). Plant nutrition. Springer, The Netherlands.Google Scholar
  76. Hou, W., X. Chen, G. Song, Q. Wang & C. C. Chang. 2007. Effects of copper and cadmium on heavy metal polluted water body restoration by duckweed (Lemna minor). Plant Physiol. Biochem. 45: 62–69.PubMedGoogle Scholar
  77. Howden, R., P. B. Goldsbrough, C. R. Andersen & C. S. Cobbett. 1995. Cadmium-sensitive, cad1, mutants of Arabidopsis thaliana are phytochelatin deficient. Plant Physiol. 107: 1059–1066.PubMedGoogle Scholar
  78. Huang, J. W., J. Chen, W. R. Berti & S. D. Cunningham. 1997. Phytoremediation of lead contaminated soil: role of synthetic chelates in lead phytoextraction. Environ. Sci. Technol. 31: 800–805.Google Scholar
  79. Hussein, D., M. J. Haydon, Y. Wang, J. Wong, J. Camakaris, J. F. Harper & C. S. Cobbett. 2004. P-type ATP-ase heavy metal transporters with roles in essential Zinc homeostasis in Arabidopsis. Plant Cell 16: 1327–1339.Google Scholar
  80. James, B. R. 2001. Remediation-by- reduction strategies for chromate-contaminated soils. Environ. Geochem. Health 23: 175–189.Google Scholar
  81. Jiang, L. Y., X. E. Yang & Z. L. He. 2004. Growth responses and phytoextraction of copper at different levels in soils by Elsholtzia splendens. Chemosphere 55: 1179–1187.PubMedGoogle Scholar
  82. Jimenez, E. M., R. Gamarra, R. O. Carpena-Ruiz, R. Millan, J. M. Penalosa & E. Esteban. 2006. Mercury bioaccumulation and phytotoxicity in two wild plant sps. of Almadenarea. Chemosphere 63: 1969–1973.Google Scholar
  83. Jonnalagadda, S. B. & G. Nenzou. 1997. Studies on arsenic rich mine dumps. II. The heavy element uptake by vegetation. J. Environ. Sci. Health Part A 32: 455–464.Google Scholar
  84. Karenlampi, S., H. Schat, J. Vangronsveld, J. A. C. Verkleij, D. van der Lelie, M. Mergeay & A. I. Tervahauta. 2000. Genetic engineering in the improvement of plants for phytoremediation of metal polluted soils. Environ. Pollut. 107: 225–231.PubMedGoogle Scholar
  85. Karin, M. 1985. Metallothioneins: proteins in search of function. Cell 41: 9–10.PubMedGoogle Scholar
  86. Keeling, S. M., R. B. Stewart, C. W. Anderson & B. H. Robison. 2003. Nickel and cobalt phytoextraction by the hyperaccumulator Berkheya coddii: implications for polymetallic phytomining and phytoremediation. Int. J. Phytorem. 5: 235–244.Google Scholar
  87. Klapheck, S., S. Schlunz & L. Bergman. 1995. Synthesis of phytochelatins and homo-phytochelatins in Pisum sativum L. Plant Physiol. 107: 515–521.PubMedGoogle Scholar
  88. Kramer, U., J. D. Cotter-Howels, J. M. Charnock, A. J. M. Baker & A. C. Smith. 1996. Free histidine as a metal chelator in plants that accumulate Nickel. Nature 379: 635–638.Google Scholar
  89. ———, I. J. Pickering, R. C. Prince, I. Raskin & D. E. Salt. 2000. Subcellular localization and speciation of nickel in hyperaccumulator and non-accumulator Thlaspi Species. Plant Physiol 122: 1343–1353.PubMedGoogle Scholar
  90. Krotz, R. M., B. P. Evangelou & G. J. Wagner. 1989. Relationship between Cadmium, Zinc, Cd-peptide and organic acid in tobacco suspension cells. Plant Physiol. 91: 780–787.PubMedGoogle Scholar
  91. Kupper, H., F. J. Zhao & S. P. McGrath. 1999. Cellular compartmentation of Zinc in leaves of the hyperaccumulator Thlaspi caerulescens. Plant Physiol. 119: 305–312.Google Scholar
  92. Lahner, B., J. Gong, M. Mahmoudian, E. L. Smith, K. B. Abid, E. E. Rogers, M. L. Guerinot, J. F. Harper, J. M. Ward, L. McIntyre, J. I. Schroeder & D. E. Salt. 2003. Genomic scale profiling of nutrient and trace elements in Arabidopsis thalliana. Nat. Biotechnol. 21: 1215–1221.PubMedGoogle Scholar
  93. Lai, H. Y. & Z. S. Chen. 2004. Effects of EDTA on solubility of cadmium, zinc and lead and their uptake by rainbow pink and vetiver grass. Chemosphere 55: 421–430.PubMedGoogle Scholar
  94. LeDuc, D. L., A. S. Tarun, M. Montes-Bayon, J. Meija, M. F. Malit, C. P. Wu, M. Abdel Samie, C. Y. Chiang, A. Tagmount, M. deSouza, B. Neuhieri, A. Bock, I. Caruso & N. Terry. 2004. Overexpression of selenocysteine methyltransferase in Arabidopsis and Indian mustard increase selenium tolerance and accumulation. Plant Physiol. 135: 377–383.PubMedGoogle Scholar
  95. Lee, J. R. D., R. R. Reeves, R. R. Brooks & T. Jaffre. 1977. Isolation and identification of a citrato-complex of nickel from nickel-accumulated plants. Phytochemistry 16: 1502–1505.Google Scholar
  96. Lee, S., J. S. Moon, T. S. Ko, D. Petros, P. B. Goldsbrough & S. S. Korban. 2003. Overexpression of Arabidopsis phytochelatin synthase paradoxically leads to hypersensitivity to cadmium stress. Plant Physiol. 131: 656–663.PubMedGoogle Scholar
  97. Li, Z. S., Y. P. Lu, R. G. Zhen, M. Szczypka, D. J. Thiele & P. A. Rea. 1997. A new pathway for vacuolar cadmium sequestration in Saccharomyces cerevisiae-YCF 11 – catalyzed transport of bis(glutathione) cadmium. Proc. Natl. Acad. Sci. USA 94: 42–47.Google Scholar
  98. Li, T. Q., X. E. Yang & X. X. Long. 2004a. Potential of using Sedum alfredii Hance for phytoremediating multi-metal contaminated soils. J. Soil Water Conserv. 18: 79–83.Google Scholar
  99. Li, Y., O. P. Dhanker, L. Carreira, D. Lee, A. Chen, J. I. Schroeder, R. S. Ballish & R. B. Meagher. 2004b. Overexpression of phytochelatin synthase in Arabidopsis leads to enhanced arsenic tolerance and cadmium hypersensitivity. Plant Cell Reports 45: 1787–1797.Google Scholar
  100. Lombi, E., F. J. Zhao, S. J. Dunham & S. P. McGrath. 2001. Phytoremediation of heavy metal contaminated soils, natural hyperaccumulation versus chemically-enhanced phytoextraction. J. Environ. Qual. 30: 1919–1926.PubMedGoogle Scholar
  101. Lovely, D. R. 1993. Dissimilatory metal reduction. Annu. Rev. Microbiol. 47: 263–290.Google Scholar
  102. Lu, Y. P., R. S. Li & P. A. Rea. 1997. AtMRP1 gene of Arabidopsis encodes a glutathione S-conjugate pump: isolation and functional definition of a plant ATP binding cassette transporter gene. Proc. Nat. Acad. Sci. 94: 8243–8248.PubMedGoogle Scholar
  103. Ma, L. Q, K. M. Komar & E. D. Kennely. (2001) Methods for removing pollutants from contaminated soil materials with a fern plant Document type and Number: United States Patent 6280500.
  104. MacDiarmid, C. W., L. A. Gaither & D. Eide. 2000. Zinc transporters that regulate vacuolar zinc storage in S. cerevisiae EMBO J. 19: 2845–2855.Google Scholar
  105. Margoshes, M. & B. L. Valte. 1957. A cadmium protein from equine kidney cortex. J. Am. Chem. Soc. 79: 4813–4814.Google Scholar
  106. Marmiroli, N. & S. C. McCutcheon. 2003. Making phytoremediation a successful technology. Pp 85–119. In: S. C. Mc Cutcheon & J. L. Schnoor (eds). Phytoremediation: transformation and control of contaminants. Wiley-interscience, Hoboken.Google Scholar
  107. Marrs, K. A. 1996. The functions and regulation of glutathione S-transferases in plants. Annu. Rev. Plant Physiol. Plant. Mol. Biol. 47: 127–158.PubMedGoogle Scholar
  108. McGrath, S. P. 1998. Phytoextraction for soil remediation. Pp 109–128. In: R. R. Brooks (ed). Plants that hyperaccumulate heavy metals. CAB International, New York.Google Scholar
  109. Meagher, R. B., C. L. Rugh, M. K. Kandasamy, G. Gragson & Wang. 2000. Engineered phytoremediation of mercury pollution in soil and water using bacterial genes. Pp 201–219. In: N. Terry & G. Banuelos (eds). Phytoremediation of contaminated soil and water. Lewis, Boca Raton.Google Scholar
  110. Meers, E., A. Ruttens, M. Hopgood, E. Lesage & F. M. G. Tack. 2005. Potential of Brassica rapa, Cannabis sativa, Helianthus annus and Zea mays for phytoextraction of heavy metals from calcareous dredged sediment derived soils. Chemosphere 61: 561–572.PubMedGoogle Scholar
  111. Mejare, M. & L. Billow. 2001. Metal binding proteins and peptides in bioremediation and phytoremediation of heavy metals. Trends Biotechnol. 19: 67–73.PubMedGoogle Scholar
  112. Min, Y., T. Boqing, T. Miezhan & I. Aoyama. 2007. Accumulation and uptake of Manganese in a hyperaccumulator Phytolacca americana. Minerals Engg. 20: 188–190.Google Scholar
  113. Misra, S. & L. Gedamu. 1989. Heavy metal tolerant transgenic Brassica napus and Nicotiana tabacum L. plants. Theor. App. Gen. 78: 161–168.Google Scholar
  114. Moreno, D. A., G. Villora, M. T. Soriano, N. Castilla & L. Romero. 2005. Sulfur, chromium, and selenium accumulated in Chinese cabbage under direct covers. J. Environ. Manag. 74: 89–96.Google Scholar
  115. Murakami, M., N. Ae & S. Ishikawa. 2007. Phytoextraction of cadmium by rice (Oryza sativa L.), soybean (Glycine max (L.) Merr.) and maize (Zea mays L.). Environ. Pollut. 145: 96–103.PubMedGoogle Scholar
  116. Murphy, A. & L. Taiz. 1995. Comparison of metallothionein gene expression and non-protein thiols in ten Arabidopsis ecotypes. Plant Physiol. 109: 945–954.PubMedGoogle Scholar
  117. Nandakumar, P. B. A., V. Dushenkov, H. Motto & I. Raskin. 1995. Phytoextraction: the use of plants to remove heavy metals from soils. Environ. Sci. Technol. 29: 1232–1238.Google Scholar
  118. Navari-izzo, F. & M. F. Quartacci. 2001. Phytorsemediation of metals. Tolerance mechanism against oxidative stress. Minera. Biotech. 13: 73–83.Google Scholar
  119. Neuhieral, B., M. Thanbichler, F. Lottspeich & A. Bock. 1999. A family of S-methylmethionine dependent thiol/selenol methyltransferases. J. Biol. Chem. 274: 5407–5414.Google Scholar
  120. Norvell, W. A. 1999. Reactions of metal chelates in soil and nutrient solution. In: J. J. Mortvedt et al. (eds). Micronutrients in agriculture. Pp.187–228. 2nd Ed. Madison, Soil Sci. Soc. Am., WIGoogle Scholar
  121. Padmavathiamma, P. K. & Y. L. Loretta. 2007. Phytoremediation Technology: hyper-accumulation metals in plants. Water Air Soil Pollut. 184: 105–126.Google Scholar
  122. Pan, A., M. Yang, F. Tie, L. Li, Z. Chen & B. Ru. 1994. Expression of mouse metallothionein-I-gene confers cadmium resistance in transgenic tobacco plants. Plant Mol. Biol. 24: 341–351.PubMedGoogle Scholar
  123. Papoyan, A. & L. V. Kochian. 2004. Identification of Thlaspi caerulescens genes that may be involved in heavy metal hyperaccumulation and tolerance. Characterization of a novel heavy metal transporting ATPase. Plant Physiol. 136: 3814–3823.PubMedGoogle Scholar
  124. Paulsen, I. T. & M. H. Saier. 1997. A novel family of ubiquitous heavy metal ion transport proteins. J. Memb. Biol. 156: 99–103.Google Scholar
  125. Pence, N. S., P. B. Larsen, S. D. Ebbs, D. L. Letham, M. M. Lasat, D. F. Garvin, D. Eide & L. V. Kochian. 2000. The molecular physiology of heavy metal transport in the Zn/Cd hyperaccumulator Thlaspi caerulescens. Proc. Nat. Acad. Sci. USA 9: 4956–5960.Google Scholar
  126. Persans, M. W., L. Huynh & D. E. Salt. 2000. A novel family of putative vacuolar metal transport proteins involved in nicekel tolerance in the nickel hyperaccumulator Thlaspi goesingense Amer. Soc. Plant Physiol. CA Abstract p. 747.Google Scholar
  127. ———, K. Nieman & D. E. Salt. 2001. Functional activity and role of cation-efflux family members in Ni hyperaccumulation in Thlaspi goesingense. Proc. Nat. Acad. Sci. USA 98: 9995–10000.PubMedGoogle Scholar
  128. Pilon-Smits, E. A. H., S. Hwang, C. Mel Iytel, Y. Zhu, J. C. Tai, R. C. Bravo, Y. Chen, T. Leustek & N. Terry. 1999. Overexpression of ATP sulfurylase in Indian mustard leads to increased selenate uptake, reduction and tolerance. Plant Physiol. 119: 123–132.PubMedGoogle Scholar
  129. ——— & M. Pilon. 2002. Phytoremediation of metals using transgenic plants. Critic. Rev. Plant Sci. 21: 439–456.Google Scholar
  130. Prasad, M. N. V. 2003. Metal hyperaccumulators in plants-Biodiversity prospecting for phytoremediation technology. Electronic J. Biotech. 6: 276–312.Google Scholar
  131. Prezemeck, E. & N. U. Haase. 1991. The binding of manganese, copper and cadmium to peptides of the xylem sap of plant roots. Water Air Soil Pollut. 57–58: 569–577.Google Scholar
  132. Raab, A., J. Feldmann & A. A. Meharg. 2004. The nature of arsenic phytochelatin complexes in Holcus lanatus and Pteris cretica. Plant Physiol. 134: 1113–1122.PubMedGoogle Scholar
  133. Raskin, I. & B. D. Ensley. 2000. Pp 352. Phytoremediation of toxic metals: using plants to clean up the environment. Wiley, New York.Google Scholar
  134. ———, R. D. Smith & D. E. Salt. 1997. Phytoremediation of metals: using plants to remove pollutants from the environment. Curr. Opin. Biotechnol. 8: 221–226.PubMedGoogle Scholar
  135. Rauser, W. E. 1990. Phytochelatins. Am. Rev. Biochem. 59: 61–86.Google Scholar
  136. ——— 1995. Phytochelatins and related peptides. Structure, biosynthesis and function. Plant Physiol 109: 1141–1149.PubMedGoogle Scholar
  137. ——— 1999. Structure and function of metal chelators produced by plants: the case for organic acids, amino acids, phytin and metallothioneins. Cell Biochem. Biophys. 31: 19–48.PubMedGoogle Scholar
  138. Rivetta, A., N. Negrini & M. Cocucci. 1997. Involovement of Ca2+ -calmodulin in Cd2+ toxicity during the early phases of radish (Raphanus sativus L.) seed germination. Plant Cell Environ 20: 600–608.Google Scholar
  139. Rogers, E. E., D. J. Eide & M. L. Guerinot. 2000. Altered selectivity in an Arabidopsis metal transporter. Proc. Nat. Acad. Sci. USA 97: 12356–12360.PubMedGoogle Scholar
  140. Rotkittikhun, P., R. Chaiyaret, M. Krutrachue, P. Pokethitiyook & A. J. M. Baker. 2007. Growth and lead accumulation by the grasses Vetiveria zizanioides and Thysanolaena maxima in lead-contaminated soil amended with pig manure and fertilizer: A green house study. Chemosphere 66: 45–53.PubMedGoogle Scholar
  141. Rugh, C. L., H. D. Wilde, N. M. Stacks, D. M. Thompson, A. O. Summers & R. B. Meagher. 1996. Mercuric ion reduction and resistance in transgenic Arabidopsis thaliana plants expressing a modified bacterial merA gene. Proc. Nat. Acad. Sci. 93: 3182–3187.PubMedGoogle Scholar
  142. ———, G. M. Gragson, R. B. Meagher & S. A. Merkle. 1998. Toxic mercury reduction and remediation using transgenic plants with a modified bacterial gene. Hort. Sci. 33: 618–621.Google Scholar
  143. ———, S. P. Bizily & R. B. Meagher. 2000. Phytoreduction of environmental mercury pollution. Pp 151–170. In: I. Raskin & B. D. Ensley (eds). Phytoremediation of toxic metals: using plants to clean- up the environment. Wiley, New York.Google Scholar
  144. Ruiz, O. N., H. S. Hussein, N. Terry & H. Danniell. 2003. Phytoremediation of organomercurial compounds via chloroplast genetic engineering. Plant Physiol. 132: 1344–1352.PubMedGoogle Scholar
  145. Salt, D. E. 2004. Update on plant ionomics. Plant Physiol. 136: 2451–2456.PubMedGoogle Scholar
  146. ——— & W. E. Rauser. 1995. MgATP-dependent transport of phytochelatins across the tonoplast of oat roots. Plant Physiol. 107: 1293–1301.PubMedGoogle Scholar
  147. ———, M. Blaylock, N. P. B. A. Kumar, V. Dushenkov, D. Ensley, I. Chet & I. Raskin. 1995. Phytoremediation: a novel strategy for the removal of toxic metals from the environment using plants. Biotechnology 13: 468–474.PubMedGoogle Scholar
  148. ———, R. D. Smith & I. Raskin. 1998. Phytoremediation. Annu. Rev. Plant Physiol. Plant Mol. Biol. 49: 643–668.PubMedGoogle Scholar
  149. ——— & U. Kramer. 2000. Mechanisms of metal hyperaccumulation in plants. Pp 231–246. In: I. Raskin & Y. B. D. Ensley (eds). Phytoremediation of Toxic Metals: Using Plants to Clean-up the Environment. Wiley, New York.Google Scholar
  150. Samuelson, A. I., R. C. Martin, D. W. S. Mok & M. C. Mok. 1998. Expression of the yeast FRE genes in transgenic tobacco. Plant Physiol. 118: 51–58.Google Scholar
  151. Santa Maria, G. F. & D. H. Cogliatti. 1988. Bi-directional Zn-fluxes and compartmentalization in wheat seedling roots. J. Plant Physiol. 132: 312–315.Google Scholar
  152. Schnept, A., T. Schrefl & W. W. Wenzel. 2002. The suitability of pde-solvers in rhizosphere modeling, exemplified by three mechanistic rhizosphere models. J. Plant Nutr. Soil Sci. 165: 713–718.Google Scholar
  153. Schnoor, J. L. 2000. Phytostabilization of metals using hybrid poplar trees. Pp 133–150. In: I. Raskin & Y. B. D. Ensley (eds). Phytoremediation of toxic metals: using plants to clean-up the environment. Wiley, New York.Google Scholar
  154. ———, L. A. Light, S. C. McCutcheon, N. L. Wolfe & L. H. Carreira. 1995. Phytoremediation of organic and nutrient contaminants. Environ. Sci. Technol. 29: A318–A323.Google Scholar
  155. Shen, Z. G. & Y. L. Liu. 1998. Progress in the study of the plants that hyperaccumulate heavy metal. Plant Physiol. Commun. 34: 133–139.Google Scholar
  156. Singer, A. C., T. Bell, C. A. Heywood, J. A. C. Smith & I. P. Thompson. 2007. Phytoremediation of mixed-contaminated soil using the hyperaccumulator plant Alyssum lesbiacum: evidence of histidine as a measure of phytoextractable nickel. Environ. Pollut. 147: 74–82.PubMedGoogle Scholar
  157. Singh, O. V., S. Labana, G. Pandey, R. Budhiraja & R. K. Jain RK. 2003. Phytoremediation: an overview of metallic ion decontamination from soil. Appl. Microbiol. Biotechnol. 61: 405–412.PubMedGoogle Scholar
  158. Skinner, K., N. Wright & E. Porter-Goff. 2007. Mercury uptake and accumulation by four sps. of aquatic plants. Environ. Pollut. 145: 234–237.PubMedGoogle Scholar
  159. Smith, R. A. H. & A. D. Bradshaw. 1979. The use of metal tolerant plant populations for the reclamation of metalliferous wastes. J. Appl. Ecol. 16: 595–612.Google Scholar
  160. ——— & ———. 1992. Stabilization of toxic mine wastes by the use of tolerant plant populations. Transactions of the Institution of Mining and Metallurgy 81: A230–A233.Google Scholar
  161. Sommer, P., G. Burguera, G. Wieshamme, J. Strauss, G. Ellersdorfer & W. W. Wenzel. 2002. Effects of mycorrizal associations on the metal uptake by willows from polluted soils: implication fro soil remediation by phytoextraction. Mitt. Osterr. Bodenkd. Gessel. 66: 113–119.Google Scholar
  162. Song, W. Y., E. J. Sohn, E. Martinoia, Y. J. Lee, Y. Y. Yang, M. Jasinki, C. Forestier, I. Hwang & Y. Lee. 2003. Engineering tolerance and accumulation of lead and cadmium in transgenic plants. Nat. Biotechnol. 21: 914–919.PubMedGoogle Scholar
  163. ———, E. Martinola, J. Lee, D. Kim, D. Y. Kim, E. Vogt, D. Shim, K. S. Chol, I. Hwang & Y. Lee. 2004. A novel family of Cys-rich membrane proteins mediates cadmium resistance in Arabidopsis. Plant Physiol. 135: 1027–1039.PubMedGoogle Scholar
  164. Steffens, J. C. 1990. The heavy-metal binding peptides of plants. Annu. Rev. Plant Physiol. Mol. Biol. 41: 553–575.Google Scholar
  165. Takashi, M., H. Nakanishi, S. Kawasaki, N. K. Nishiawa & S. Mori. 2001. Enhanced tolerance of rice to low iron availability in alkaline soils using barley nicotinamide aminotransferase genes. Nat. Biotechnol. 19: 466–469.Google Scholar
  166. Thornton, B. 1991. Indirect compartmental analysis of copper in ryegrass roots: comparison with model systems. J. Exp. Bot. 42: 183–188.Google Scholar
  167. Tong, Y. P., R. Kneer & Y. G. Zhu. 2004. Vacuolar compartmentalization: a second-generation approach to engineering plants for phytoremediation. Trends Plant. Sci. 9: 7–9.PubMedGoogle Scholar
  168. Udom, A. O. & F. O. Brady. 1980. Reactivation in vitro of zinc-requiring apoenzymes by rat liver zinc-thionein. Biochem. J. 187: 329–335.PubMedGoogle Scholar
  169. Van der Zaal, B. J., L. W. Neuteboom, J. E. Pinas, A. N. Chardonnen, J. A. C. Verkleij & P. J. J. Hooykaas. 1999. Overexpression of a novel Arabidopsis gene related to putative Zinc transporter genes from animals can lead to enhanced Zinc resistance and accumulation. Plant Physiol. 9: 1107–1114.Google Scholar
  170. Van Huysen, T., S. Abdel-Chaney, K. L. Hale, D. LeDuc, N. Terry & E. A. H. Pilon-Smits. 2003. Overexpression of cystathione-gamma-synthase enhances selenium volatilization in Brassica juncea. Planta 218: 71–78.PubMedGoogle Scholar
  171. ———, N. Terry & E. A. H. Pilon-Smits. 2004. Exploring the selenium phytoremediation potential of transgenic Indian mustard over expressing ATP sulfurylase or cystathione gamma synthase. Int. J. Phytorem. 6: 111–118.Google Scholar
  172. Vatamaniuk, O. K., S. Mari, Y. P. Lu & P. A. Rea. 1999. AtPCS1, a phytochelatin synthase from Arabidopsis: isolation and in vitro reconstitution. Proc. Nat. Acad. Sci. USA 96: 7110–7115.PubMedGoogle Scholar
  173. Verret, G. A., J. F. Briat & C. Curie. 2003. Dual regulation of the Arabidopsis high-affinity root iron uptake system by long –distance signals. Plant Physiol. 132: 796–804.Google Scholar
  174. Verret, F., A. Gravot, P. Auroy, N. Leohardt, P. David, L. Nussaume, A. Vavasseur & P. Richaud. 2004. Overexpression of AtHMA4 enhances root-to-shoot translocation of Zinc and Cadmium and plant metal tolerance. FEBS Lett. 576: 306–312.PubMedGoogle Scholar
  175. Vert, G. A., N. Grotz, F. Dedaldechamp, M. L. Guerinot, J. F. Briat & C. Curie. 2002. IRT1, an Arabidopsis transporter essential for iron uptake from the soil and for plant growth. Plant Cell 14: 1223–1233.PubMedGoogle Scholar
  176. Vadenhov, H. & M. V. Heese. 2004. Phytoextraction for clean-up of low level uranium contaminated soil evaluated. J. Environ. Rad. 72: 41–45.Google Scholar
  177. Vázquez, M. D., J. Barceló, C. Poschenrieder, J. Mádico, P. Hatton, A. J. M. Baker & G. H. Cope. 1992. Localization of zinc and cadmium in Thlaspi caerulescens (Brassicaceae), a metallophyte that can hyperaccumulate both metals. J. Plant Physiol. 140: 350–355.Google Scholar
  178. ———, C. Poschenreider, J. Barcelo, A. J. M. Baker, P. Hatton & G. H. Cope. 1994. Compartmentation of zinc in roots and leaves of the zinc hyperaccumulator Thlaspi caerulescens J& C Presl. Bot. Acta. 107: 243–250.Google Scholar
  179. Vogeli-Lange, F. & G. J. Wagner. 1989. Subcellular localization of cadmium and cadmium-binding peptides in tobacco. Implication of a transport function for cadmium-binding peptides. Plant Physiol. 92: 1086–1093.Google Scholar
  180. Von Wiren, N., S. Klair, S. Bansal, J. F. Briat, H. Khodr, T. Shiori, R. A. Leigh & R. C. Hider. 1999. Nicotinamide chelates both Fe III and Fe II. Implications for metal transport in plants. Plant Physiol. 119: 1107–1114.Google Scholar
  181. Wei, C. Y., T. B. Chen & Z. C. Huang. 2002. Cretan bake (Pteris cretica L): an arsenic accumulating plant. Acta Ecologia Sinica 22: 777–782.Google Scholar
  182. Williams, L. E., J. K. Pittman & J. L. Hall. 2000. Emerging mechanisms for heavy metal transport in plants. Biochem Biophys Acta 1465: 104–126.PubMedGoogle Scholar
  183. Winge, D. R., J. A. Graden, M. C. Posewitz, L. J. Martins, L. T. Jansen & J. R. Simon. 1997. Sensors that mediated copper-specific activation and repression of gene expression. J. Biol. Inorg. Chem. 2: 2–10.Google Scholar
  184. Xiang, C. & D. J. Oliver. 1998. Glutathione metabolic genes coordinately respond to heavy metals and jasmonic acid in Arabidopsis. Plant Cell 10: 1539–1550.PubMedGoogle Scholar
  185. Yang, X., X. Jin, Y. Feng & E. Islam. 2005. molecular mechanisms and genetic basis of heavy metal tolerance in plants. J. Integ. Biol. 47: 1025–1035.Google Scholar
  186. Zayed, A., S. Gowthaman & N. Terry. 1998. Phytoaccumulation of trace elements by wetland plants. J. Environ. Qual. 27: 715–721.CrossRefGoogle Scholar
  187. Zhang, X. H., J. Liu, H. T. Huang, J. Chen, Y. N. Zhu & D. Q. Wang. 2007. Chromium accumulation by the hyperaccumulator plant Leersia hexandra Swartz. Chemosphere 67: 1138–1143.PubMedGoogle Scholar
  188. Zhou, J. M. & P. B. Goldsbrough. 1995. Structure, organization and expression of the metallothionein gene family in Arabidopsis. Mol. Gen. Genet. 248: 318–328.PubMedGoogle Scholar
  189. Zhu, Y. L., E. A. H. Pilon-Smits, A. S. Tarun, S. U. Weber, L. Jouanin & N. Terry. 1999. Cadmium tolerance and accumulation in Indian mustard is enhanced by overexpressing γ-glutamylcysteine synthetase. Plant Physiol. 121: 1169–1177.PubMedGoogle Scholar

Copyright information

© The New York Botanical Garden 2009

Authors and Affiliations

  1. 1.Molecular Ecology Laboratory, Department of Botany, Faculty of ScienceHamdard UniversityNew DelhiIndia
  2. 2.Department of Plant Production, College of Food & Agricultural SciencesKing Saud UniversityRiyadhSaudi Arabia

Personalised recommendations