Some Three-Dimensional Aspects of Ceratocystis Ulmi as Observed by High-Voltage Electron Microscopy

SUMMARY

Resting and germinated conidia and synnemal hyphae of Ceratocystis ulmi were fixed by conventional methods for electron microscopy. Whole cells were dried by the critical-point method and by freeze-drying. Conidia and hyphae were also embedded and cut in 1-μm sections. All specimens were examined in a high-voltage electron microscope. Stereo pair photographs show three-dimensional features of the fungal cells. Of the preparative procedures tested, permanganate fixation followed by embedding and thick sectioning was found to be the best for studying C. ulmi by high-voltage electron microscopy. Some methods of viewing stereo pairs are also described. High-voltage electron microscopy is recommended as a useful tool to augment other methods of examining three-dimensional details of fungal cells.