ABSTRACT
The ability of ectomycorrhizal fungal species to tolerate high levels of heavy metals in the environment was shown in a survey of mushrooms along a pollution transect in Sweden by Rühling and Söderström (1990) in which the dominant contaminants in the humic soil horizon were As, Cu, Cd, Pb, and Zn. They showed that the abundance and diversity of fungi decreased with increasing pollutant loading, but that the ectomycorrhizal species were more tolerant of high metal concentrations than saprotrophs. Indeed, Rühling et al. (1984) showed that the ectomycorrhizal fungus Laccaria laccata was the most tolerant fungus to heavy metal pollutants, but that the number of microfungi isolated onto agar from soil did not decrease with increasing metal loading. Common species, such as Penicillium and Oidiodendron, did decrease, but some species, such as Paecilomyces and several sterile mycelial forms, were only found in the most polluted sites.
