Effect of heavy metals on cultural and morphological growth characteristics of halotolerant Penicillium morphotypes.

Four different morphotypes of halotolerant Penicillium isolated from mangroves and salterns, selected on the basis of their morphological dissimilarities, namely, monoverticillate, biverticillate symmetric, biverticillate asymmetric and terverticillate, were studied for their response to the presence of heavy metals - lead, copper and cadmium salts. Lead was the most easily tolerated of the heavy metals tested, and caused the least variations in cultural and morphological characteristics, while cadmium was the most toxic, causing significant cultural and morphological variations. More striking was the observation that resistance to the heavy metals was highest by the terverticillate Penicillium, decreasing in the biverticillate isolates, the monoverticillate isolate showing the least resistance.