Spore attachment in fungi with special reference to freshwater hyphomycetes

• Main Author: Read, S. J.
• Published: University of Portsmouth 1990
• Subjects: 580; Botany
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237285

Conidia of species of aquatic Hyphomycetes were isolated. axenically cultured and then induced to sporulate in the laboratory. Ten species with diverse conidium morphologies and germination responses were selected for examination at the light microscope and scanning and transmission electron microscope levels. The selected species were: Anguillospora crassa; Articulospora tetracladia: Clavariopsis aquatica: Dimorphospora foliicola; Heliscus lugdunensis; Lemonniera aquatica; Mycocentrospora filiformis; Tetracladium marchalianum; Tumularia aquatica; Varicospol'ium elodeae. fit is shown that the substratum has little effect on germination but that mucilage secretion and appressorium formation ar~_increased on substrata with high surface energies. Attachment. germination. protoappressorium and appressorium formation were more rapid on natural than artificial substrat~., Studies on the strengths of attachment of newly settled conidia using the Fowler Radial Flow Chamber show that tetraradiate conidia are initially more strongly attached than sigmoid conidia and that ovoid conidia are the least well attached. This is related to the number of contact points with the substratum~ The chemistry. texture and morphology of the mucilages formed by each species of aquatic hyphomycete is different and the mucilage on the conidia is frequently distinct from that on the germination structures. Mucilaginous sheaths i are ubiquitous on hyphae and appressoria. The influence of germination and appressorium formation on the strength of attachment was examined in the Fowler Radial Flow Chamber and it is shown that germ tubes. hyphae and. particularly. appressoria increase the strength of attachment to the substratum. The development of attachment structures also serve to reduce the initial differences in adhesion between the individual species.