Environmental scanning electron microscopic observation of the hyphal sheath and mycofibrils in Postia placenta.

Environmental scanning electron microscopic observations of Postia placenta grown on a defined medium and on red spruce wood allowed for the examination of the hydrated sheath of P. placenta. In the wood environment, mature hyphae that were not adhering to the substrate were observed to have a mycofibrillar morphology whereas hyphal tips and branch points had a smooth sheath morphology. A mycofibrillar adhesive matrix was observed on the hyphae growing on glass slides in the defined medium. These morphologies for hyphal sheaths in P. placenta are similar to those previously described by investigators from other laboratories who have used traditional electron microscopic preparative protocols that include dehydration steps. The potential future usefulness of environmental scanning electron microscopic technology in the study of the fine details of extracellular matrices is briefly discussed.