Abstract

A. O. Oghenekaro, J. A Okhuoya and E. O Akpaja

The effect of three heavy metals, that is, lead, zinc and copper, on the growth of Pleurotus tuberregium, was investigated. Lead carbonate, zinc carbonate and copper sulphate were added to the mushroom substrate at concentrations of 0.1, 0.5, 1.0 and 2.0 g/250 g of substrate. Two sets were prepared using spawn and sclerotia as inocula. On a mycelial density rating, ranging from 0 - 5, the spawn -inoculated treatment was higher than that of the sclerotia. The average mycelial density was highest in coppercontaminated substrate that was inoculated with spawn, with a mean value of 5.0, while the lowest was in copper-contaminated substrate that was inoculated with sclerotia, with a mean value of 2.0. Fruit bodies were formed only in the copper-contaminated substrate at concentrations of 1.0 and 2.0 g/ 250 g of substrate. Shrinkage of the mushroom fruit body occurred seven days after formation of primordia. Biological efficiency of the harvested sporophores was 0.01 and 0.02%, respectively. There was a general inhibition of fruit body development by the heavy metals, except in the two treatments with copper.