CHARACTERIZATION OF THE SPINULE WALL OF THE TRUFFLE ECTOMYCORRHIZAE BY ULTRASTRUCTURAL CYTOCHEMISTRY

Spinules are the typical structures of the Tuber mycorrhizae. They eme rge from the outer zone of the mantle. Spinules show a morphological d iversity depending on the fungal species involved in the association. Ultrastructural study on the spinules of Tuber ectomycorrhiza has been carried out using transmission electron microscopy. These structures are characterized by much thicker walls than hyphal walls of the mantl e and by quickly degenerating cytoplasm. Dead spinule walls develop ou tgrowths on their outer surface which consists of up to four layers. T he outer layer is strongly electron opaque and is limited by a thin me mbrane. The underlying layer is clear. It surrounds a layer which cons ists of radiant fibrils. The inner wall layer is very dense and freque ntly discontinuous.