• ectomycorrhiza;
  • ultrastructure;
  • host-fungus interface;
  • symbiosis;
  • transfer cells;
  • Pinus


Ultrastructural analysis of the host–fungus interface of mycorrhizas synthesized between Sutilus bovinus and Pinus sylvestris in media containing high concentrations of glucose reveals abnormalities of behaviour in both fungus and host. Vigorous fungal growth leads in some cases to isolation and death of host cortical cells. In other host cells, the wall adjacent to the fungus produces irregular ingrowths closely followed by the host plasmalernma. The cytology of these host cells is indicative of high physiological activity. Histochemical analysis shows the protuberances to be of a material similar to that of primary cell walls but with deposition of callose occurring late in their development. It is suggested that these structures may either represent a defence reaction on the part of the host to the presence of the fungus or that they may be similar to those wall ingrowths produced in transfer cells. Analogies between these structures and the latter are drawn and their possible function is discussed in relation to host and fungus nutrition and other types of transfer cell systems.