Fungal adhesion in aquatic hyphomycetes

The attachment of propagules of aquatic fungi often takes place under turbulent conditions, i.e. spores of marine lignicolous fungi and conidia of freshwater Hyphomycetes. It has been demonstrated that attachment in Lemonniera aquatica is effected by three arms of the conidium making contact with the surface and forming appressoria. In this study the mechanisms of attachment of conidia of 10 aquatic Hyphomycetes to a variety of natural and artificial substrata were followed at the light microscope and scanning electron microscope levels.Five species produced appressoria, while in the remaining species attachment and subsequent retention to the substratum was effected solely by the production of mucilage. Examination of selected appressorium-forming species in the transmission electron microscope showed that conidium attachment involved the production of mucilage in the regions of initial contact and only then were appressoria formed. The ecological significance of appresoiria to the aquatic Hyphomycetes is discussed.