Translocation of cadmium and mercury in straw columns colonized by the fungus Pleurotus cornucopiae Paul ex Fr.

Abstract

Using straw columns colonized by the lignocellulytic fungus Pleurotus cornucopiae, translocation of 109Cd and 203Hg in the substrate-mycelium complex and via the substrate-mycelium complex into the fruiting bodies was studied. The translocation patterns generated were metal specific and were influenced by the temperature and the physiological conditions of the mycelium (‘growing’ mycelium, ‘established’ mycelium, reproductive stage). Under all conditions, generally more mercury than cadmium was translocated. In ‘growing’ mycelia, for instance, an average of about seven times more mercury than cadmium was translocated. Translocation was greatly enhanced, when fruiting bodies were present. Up to 7% and 20% (average: 3.5% and 12%) of the applied cadmium and mercury, respectively, were found in the fruiting bodies. In ‘old’ columns bearing fruiting bodies (colonized for more than 50 days by the fungus) considerably more heavy metal (up to 45% of the applied radioactivity) was released from the point of application than in younger columns. With one exception, no substantial differences in the translocation patterns of the label in relation to the direction of mycelial growth could be detected.