Electron microscopy of germinating ascospores of Saccharomyces cerevisiae.

The wall of mature ascospores of Saccharomyces cerevisiae showed in sections under the electron microscope a dark outer layer and a lighter inner layer. The latter was composed of a greyish inner part and a light outer part. During germination, the spore grew out at one side and the dark outer layer was broken. Of the light inner layer, the inner greyish part became the wall of the vegetative cell, but the extended part of the cell had a new wall.