Toxic element filtering in Rhizopogon roseolus Pinus sylvestris mycorrhizas collected from calamine dumps

Rhizopogon roseoilus/Pinus sylvestris mycorrhizas collected from calamine dumps (rich in Cd, Zn and Pb) were analysed by electron energy loss spectroscopy (EELS) connected to a transmission electron microscope. The distribution of potentially toxic elements within selected mycorrhizas was shown. Complementary data were obtained by cytochemical tests revealing the distribution of polysaccharides (PATAg) and cysteine-rich proteins (Gomori-Swift reaction). The mycorrhizas investigated were characterized by the accumulation of Cd and Al in the fungal mantle and a gradual decrease of these elements was observed along the Hartig net towards the inside of the root, suggesting a filtering effect. Both of these elements were detected in the electron-opaque deposition in the vacuoles, in periplasmic spaces as well as in the extracellular material. A comparatively high level of these elements was found in the phenolic material of dead cortical cells. This was probably an additional source of toxic elements for the mycelium which was colonizing the tannin cells.