Influence of Zn and Pb on Rhizopogon roseolus mycelium - Energy dispersionspectroscopy and cytochemical investigation

Mycelium isolated from fruitbodies of Rhizopogon roseolus, collected from c alamine wastes in Poland, was cultivated on agar media supplemented with Zn or Pb salts. The stimulation of exudate production by the aerial mycelium and the mycelium growing on the surface of the media, accompanied by the ch ange of mycelium pigmentation, was found as a result of Zn application. The presence of Pb resulted mainly in the stimulation of crystalloid productio n on the surface of mycelium, in direct contact with the medium. Exudate dr oplets formed on the surface of mycelium cultivated on media with and witho ut the Zn addition, were investigated by means of cytochemical tests (PATAg and Gomori-Swift reaction). In the control media most droplets gave a diff used, positive reaction to both tests. In media supplemented with Zn salts, besides the droplet-like material described in the control also another ki nd of exudate was observed. It was characterized by the collar showing a po sitive Gomori-Swift reaction, while the rest of the exudate had an oily app earance and gave a faint or no reaction to both tests. Comparative research by means of scanning electron microscopy accompanied by energy dispersion spectroscopy, was carried out showing the differences in exudate and in myc elia composition as a result of the Zn and Pb presence in the medium.