EFFECT OF SOME HEAVY-METALS ON THE MYCELIAL GROWTH OF ACHLYA-RACEMOSAAND ALATOSPORA-ACUMINATA

Achlya racemosa and Alatospora acuminata cultures were subjected to va rious levels of NiCl2, CdCl2, Pb(N0(3))2 and CuSO4. The mycelial dry w eight of two fungal species decreased with the raise of the levels of all heavy metal salts used. The toxicity of these heavy metals correla ted to some abiotic factors such as pH, temperature and organic matter (peptone and yeast extract) was examined. The toxicity of NiCl2, Pb(N O3)(2) and CuSO4 was reduced with the raise of pH value irrespective t o either dose used or the fungus tested whereas toxicity of CdCl2 was enhanced. The raise of temperature than 20 degrees C induce the toxici ty of all tested heavy metals. Increasing the concentrations of either peptone or yeast extract from 0.25 to 1.50 % reduce the toxicity of f our tested heavy metals whatever the dose used.