Spore Cleavage in Two Myxomycetes, Myxomycetes, Spore Cleavage, Spore Wall Ornamentation
Processes of spore cleavage, spine deposition, and continuous wall formation have been followed in Didymium iridis and Physarum flavicomum, using electron microscopy combined with cytochemistry. The periodic acid silver hexamine (PASH) technique for demonstration of polysaccharide at the ultrastructural level has been employed. Developing sporangia were fixed at 30 min. intervals. Six hours after plasmodia form noticeable blebs on the agar, the surface membrane begins to invaginate and cleaves out spores. Flattened cytoplasmic vesicles originating from dictyosomes contribute membrane to the cleavage furrows as they grow centripetally. As soon as the spores have been cleaved, spine formation begins. Spines are deposited in regions where membranes of adjacent protospores touch. Small vesicles containing polysaccharide are formed at the Golgi apparatus and move to the cell surface, fusing with the membrane. Material thus secreted forms the spines. After the spines have been laid down, the continuous wall layers are formed underneath. The continuous layers stain only weakly for polysaccharide, while the spines stain strongly.
Proceedings of the Iowa Academy of Science
© Copyright 1974 by the Iowa Academy of Science, Inc.
Aldrich, Henry C.
"Spore Cleavage and the Development of Wall Ornamentation in Two Myxomycetes,"
Proceedings of the Iowa Academy of Science: Vol. 81:
, Article 11.
Available at: http://scholarworks.uni.edu/pias/vol81/iss1/11