Problems with Fixation and Embedding of Arbuscular Mycorrhizal Fungi (Glomales)

In order to conduct ultrastructural studies to clarify the nature of the spores formed in Glomales, an order of arbuscular mycorrhizal fungi, techniques for fixation and embedding of these spores were tested. Of nine methods, none was effective for fixation of Acaulospora, Gigaspora, and Scutellospora spores, but one was efficient for fixation of Glomus. This method included fixation with glutaraldehyde in a microwave oven, and breaking the spores under liquid nitrogen before postfixation with osmium tetroxide. For spore walls, however, most of the techniques were satisfactory for all of the genera tested.