Heavy Metal Resistance and Accumulation Characteristics in Willows |
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Authors: | Tracy Punshon Nicholas Dickinson |
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Affiliation: | 1. School of Biological and Earth Sciences , Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, England Phone: +01144(151)231-2190 Fax: +01144(151)231-2190;2. University of Georgia, Savannah River Ecology Laboratory , Drawer E. Aiken, SC, 29802, USA Phone: (803)725-5956 Fax: (803)725-5956 E-mail: punshon@srel.edu besndick@livjm.ac.uk;3. School of Biological and Earth Sciences , Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, England Phone: +01144(151)231-2190 Fax: +01144(151)231-2190 |
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Abstract: | The resistance of Salix to Cu, Cd, Ni, and Zn was investigated in hydroponic culture, with phytoextraction potential evaluated for Cu. Root elongation (indicative of resistance level) was significantly affected, with considerable variation between and within individual clones. Resistance appeared to be clone- or hybrid-specific, rather than species-specific. S. caprea clones (and hybrids) were among the most resistant, but a secondary S. caprea clone from a different provenance was much less tolerant. S. viminalis and S. triandra clones were the most sensitive. Highest resistance was found in response to Cd, while Cu and Ni were extremely toxic. A resistant S. caprea ecotype originating from a metalliferous mine spoil was identified using this technique. Copper concentration reached a maximum of 2000, 400, and 82 μg g-1 (d.wt) in roots, wood, and foliage, respectively, after 1 month in hydroponic culture. The level of variation in the response of Salix to metals may cause difficulties in phytoremediation screening programs, but may be essential in providing genetic variation for selection of metal resistance traits, where the contaminant profile is heterogeneous, mixed, or subject to change. Clone selection for metal phytoextraction is feasible, but a longer field-scale study on metal-contaminated soils is needed before their role in phytoremediation can be confirmed. |
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Keywords: | Salix trees heavy metals phytoremediation |
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