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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/2101

Title: Solubilization of toxic metal minerals and metal tolerance of mycorrhizal fungi
Authors: Fomina, MA
Alexander, I.J.
Gadd, GM
Issue Date: 2005
Citation: SOIL BIOLOGY & BIOCHEMISTRY, 37(5). p. 851-866
Abstract: This work investigates the ability of ericoid mycorrhizal (ErM) and ectomycorrhizal (EcM) fungi to solubilize different toxic metal (Cd, Cu, Ph, Zn)-containing minerals. Minerals were incorporated into solidified agar media and solubilization assessed by measuring clearing of the agar after fungal growth. Measurement of radial growth and biomass dry weight provided indications of metal tolerance: accumulated metal in the biomass was measured by atomic absorption spectrophotometry. Metal tolerance and solubilizing ability varied widely between different mineral and fungal species, and strains derived from sites of differing degrees of metal pollution. Zinc phosphate exhibited the least toxicity and was the easiest to solubilize by the majority of tested fungal isolates. Solubilization of toxic metal minerals was connected with both the pH of the medium and growth and tolerance of fungi and it seems that acidification of the medium was the main mechanism of mineral dissolution for most of the mycorrhizal fungi studied. A very strong lethal effect was observed for ectomycorrhizal isolates (> 60% of strains) in the presence of Pb phosphate, carbonate, sulphide and tetraoxide. In contrast, ericoid mycorrhizal isolates were able to grow on Pb-mineral-amended media. A significant proportion of ericoid mycorrhizal cultures (70-90%) solubilized Cd and Cu phosphates and cuprite. None of the ericoid mycorrhizal and ectomycorrhizal fungi were able to produce a clear zone in Pb mineral -containing agar. However, many fungi were able to accumulate mobilized Ph in their mycelia. Differences in toxic metal mineral tolerance, mineral solubilization and metal uptake between populations isolated from metal-polluted and uncontaminated sites were related to the toxic metal which was the main pollutant in the original contaminated environment. In general, metal-tolerant fungi grew and solubilized toxic metal minerals better than non-tolerant isolates. (c) 2004 Elsevier Ltd. All rights reserved.
Notes: Univ Dundee, Sch Life Sci, Biol Sci Inst, Div Environm & Appl Biol, Dundee DD1 4HN, Scotland. Univ Aberdeen, Dept Plant & Soil Sci, Aberdeen AB24 3UU, Scotland. Limburgs Univ Centrum, Environm Biol, B-3590 Diepenbeek, Belgium.Gadd, GM, Univ Dundee, Sch Life Sci, Biol Sci Inst, Div Environm & Appl Biol, Dundee DD1 4HN, Scotland.g.m.gadd@dundee.ac.uk
URI: http://hdl.handle.net/1942/2101
DOI: 10.1016/j.soilbio.2004.10.013
ISI #: 000228242300006
ISSN: 0038-0717
Category: A1
Type: Journal Contribution
Validation: ecoom, 2006
Appears in Collections: Research publications

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