INFLUENCE OF HEAVY-METALS ON GERMINATION OF ARBUSCULAR-MYCORRHIZAL FUNGAL SPORES IN SOILS

A simple device (sandwich of spores in Path dishes) was used to study the effect of soils with different heavy metal concentrations, and dif ferent origins of metals, on spore germination of Glomus mosseae and o f two arbuscular-mycorrhizal fungal cultures isolated from polluted so ils. Germination of G. mosseae spores was reduced to 4 % in the soil w ith the highest Cd, Zn and Pb concentrations. However, with still high cadmium concentrations varying from 1 to 100 mg/kg(-1), the effect of metals was mitigated or increased depending on pH, phosphorus concent ration and soil texture. In two soils containing 17 and 3 ppm Cd, meta ls did not affect the germination of G. mosseae spores due to their lo w availability. However, indigenous spores cultures from both soils we re more tolerant to high cadmium concentrations than G. mosseae.