[Electron microscopical studies of differentiating processes in mosses : I. Problems of preserving the fine structure].

For the demonstration of the ultrastructure of the cells from Riella and Funaria by electron microscopy, special conditions were found to be necessary for preservation of all known structural elements. The best results were obtained by fixation in a buffered mixture of formaldehyde (0.5 or 1.5%) and glutaraldehyde (0.5 or 1.5%) for 15-20 hours in the cold. The postfixation was performed in 1% OsO4 for 3 hours. Using these conditions an excellent preservation of all structural elements is demonstrated in young and old cells of the mosses. The conditions used in our experiments are compared with those from other experiments performed previously by other investigators who were not so successful in overcoming the special difficulties encountered in the study of mosses.