Reaction of some decomposer basidiomycetes to toxic elements .

Cultures of 15 decomposer basidiomycete samples were examined for resistance to Al, As, Be, Cd, Co, Cr, Cu, H, Hg2(I), Hg(II), Ni, Pb, Sn, and Zn using a micro-well technique. Aluminium was found to be slightly toxic; Be, Zn, and As moderately toxic; Cr, Cu, Sn, Co, Hg(II), Ni, Hg2(I), and Pb toxic; and Cd very toxic. Generally, the fungitoxicity rises with increasing electronegativity of the element, if we exclude As and Cd. According to the fungal reactions, the elements can be arranged into several groups with similar toxicity: The Cu-Hg2(I)-Hg(II)-Ni group, the Al-Cr-H group, and the As-Pb-Zn group. Tin is related both to the first and the second group. Beryllium, Cd, and Co occupy more isolated positions. Resistance to Hg, Ni, and Cu generally increases with the ability of the fungus to produce phenoloxidases, especially the intracellular tyrosinase. One explanation may be that these fungi decompose the substances that actually bind Hg, Ni, and Cu and hence protect them from the toxic action. Resistance to Al and H (expressed as pH) may be higher in fungi from poor soils. The physiological effect of soluble Al on fungi seems to depend more on its ability to release H3O+ in the medium than on the toxic action of the metal itself. On the other hand, resistance to Cd is possibly higher in fungi from rich soils, probably because toxicity of Cd usually increase with pH.

H°iland, K. 1995. Reaction of some decomposer basidiomycetes to toxic elements. - Nord. J. Bot. 13: 305-318.