Ultrastructure des ectomycorhizes synthétiques à Hebeloma alpinum et Hebeloma marginatulum de Dryas octopetala

Abstract

Ectomycorrhizas of Dryas octopetala (Rosaceae) were synthesized with two alpine species of Hebeloma and observed by means of transmission electron microscopy. The mycorrhizas studied here were harvested at the time of fruiting of the associated fungi. The ultrastructure of the mycelial sheath, Hartig net, host cortical cells, and host–mycobiont interface was thus defined from very active, functional, living structures. Following analysis of the results, an interpretation of hyphal morphogenesis in the sheath and in the Hartig net is proposed.