Cadmium-Accumulating Plants

3 Role of Metal Ligands in Cadmium Uptake, Transport, and Storage. 382 

Fachbereich Biologic, Universitat Konstanz, D-78457 Konstanz, Germany e-mail hendrik.kuepper um-konstanz.de 

Institut fur Anorganische Chemie, Universitat Ziirich, WmterthurerstraBe 190, CH-8057 Zurich, Switzerland 

Sigel (eds.). Cadmium From Toxicity to Essentiality, Metal Ions in Life Sciences II, DOI IO.I007/978-94-007-5I79-8 I2, 

Keywords excluder plants hyperaccumulator plants indicator plants natural overexpression of transport proteins phytoremediation phytomining vacuolar metal sequestration 

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Brassica juncea (brown mustard) is a plant that accumulates heavy metals like cadmium in its roots. This metal accumulating habit can be used for removing heavy metals from polluted soils. Interesting question, how the Cd-induced stress influences the photosynthetic activity of this cadmium accumulating plant. SECM method allows measuring the immediate stress response at microscale, showing the change of stomata structure and photosynthetic activity. 

Bingham F.T., Page A.L., Mahler R.J., Ganji T.J. Growth and cadmium accumulation of plants grown on a soil treated with a cadmium-enriched sewage sludge. J Environ Qual 1975 4 207-211. 

Zhu, Y. L., Pilon-Smits, E. A. H., Jouanin, L., and Terry, N., 1999a, Overexpression of glutathione synthetase in Indian mustard enhances cadmium accumulation and tolerance, Plant Physiol. 119 73-79. 

Edehnan, L., E. Czamecka, and J.L. Key. 1988. Induction and accumulation of heat shock-specific poly (A+) RNAs and proteins in soybean seedlings during arsenite and cadmium treatments. Plant Physiol. 86 1048-1056. 

Lux, A., Sottnikova, A., Opatma, J., Greger, M., 2004. Differences in structure of adventitious roots in Salix clones with contrasting characteristics of cadmium accumulation and sensitivity. Phytiol. Plant 120, 537-545. 

This chapter summarized recent advances and earlier important works dealing with the accumulation of cadmium in plants, with a special focus on Cd hyperaccumulators. As described in detail above, a lot of progress has been made in... 

In the profiles of the core from the industrial area, mercury displays the highest accumulation. Mercury in this area, close to the industrial district, has probably derived from a large chloralkali plant which has employed mercury cathodes since the fifties. Whereas, at present, very severe measures are taken to prevent mercury spills into the Lagoon, in the past, polluted waters and solid materials were discharged almost untreated. In the most superficial strata a marked decrease in the accumulations is, in fact, recorded. Lead and Cd accumulations are lower here by a factor of 5-10. The presence of cadmium in the sediments of the Lagoon has been referred to sphalerite (ZnS) processing on the basis of a strict concomitant... 

Hi) Poly amines. In many respects the role of poly amines in plant functioning is still mysterious after many years work. They are almost certainly involved in the control of growth and development through their interactions with nucleic acids and membranes (Smith, 1985). There is increasing circumstantial evidence for their involvement, especially of putrescine, in plant responses to a wide range of stresses including pH, Mg deficiency, osmotic shock, cold, SO2 pollution, and cadmium and ammonium toxicity (Smith, 1985). It remains to be determined, however, how, and indeed whether, putrescine accumulation in response to these diverse stresses is beneficial. 

Standards imposed to the industrial waste streams charged in heavy metals are more and more drastic in accordance with the updated knowledges of the toxicity of mercury, cadmium, lead, chromium... when they enter the human food chain after accumulating in plants and animals (Forster Wittmann, 1983). Nowadays, the use of biosorbents (Volesky, 1990) is more and more considered to complete conventional (physical and chemical) methods of removal that have shown their limits and/or are prohibitively expensive for metal concentrations typically below 100 mg.l-i. 

Salt D.S., Prince R.C., Pickering I.J., Raskin I. Mechanisms of cadmium mobility and accumulation in Indian mustard. Plant Physiol 1995 109 1427-1433. 

Heavy metals in the environment, especially their accumulation in soils, is a serious environmental problem which the whole world faces (Du et al. 2005). The farmland soils are an important media of the ecological cycle of Cadmium, and its harm to human health can t be neglected (Wu et al. 2004). Heavy metal migration, transformation and toxicity to plants in soil are directly influenced by the quantity proportions of various forms (Zhu et al. 2002). The toxicity of water-extractable and adsorbed and exchangeable metals are the greatest, and residual metals is the lowest (Liu etal. 2002). Different forms have different bioavailability thus their influences on the environment and human health are different. It is critical to have a good understanding of Cadmium forms in soil. This paper describes the Cadmium forms in the acid soils of eastern China. 

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