Light and electron microscopy of the host–fungus interaction in the achlorophyllous gametophyte of <i>Botrychium lunaria</i>

Abstract

The host–fungus interaction between the achlorophyllous gametophyte of Botrychium lunaria and its fungal endophyte was studied by means of light and electron microscopy. Aseptate hyphae with a multilayered cell wall formed intracellular coils. The interface consisted of a thick layer of fibrillar matrix material, an electron-translucent zone, and the host plasmalemma. Several vesicles that show different stages of development and degeneration occurred within one host cell. Degenerating vesicles were encased by large amounts of an electron-translucent material. Arbuscules were not observed. The fungus did not infect the young sporophyte but degenerated within intact gametophyte cells. Key words: Botrychium lunaria, gametophyte, mycorrhiza, ultrastructure.