2.3 Comparison of the ultrastructure of dormant and non-dormant chlamydospore
Under scanning electron microscope, the dormant spores did not germinate after 12 h of culture (Figure 3A), but the shape of spores were round and full. The non-dormant spores had germinated (Figure 3B), the germination tubes were extended, and the surface was locally deflated. There were nodules on the surface of both types of spores but no obvious differences. The transmission electron microscope (TEM) image shows the internal structure of the spore. The spore wall is composed of outer shell, outer membrane and cortex from the outside in (Figure 3C, 3D, 3E & 3F). The white transparent part of the spore wall, with certain electron transmittance, is the inner wall of the spore, or the cortex. Due to the high electron permeability, the inner wall of the dormant spore forms a thick white zona pellucida, which is significantly thicker than that of the inner wall of the non-dormant spore, and several times the difference can be observed. The cytoplasm of non-resting spores is full of many round, regular and small liposome contents, and there are also a few glycogen particles with low electron density. As the resting spores aging process, many cytoplasmic vesicles gradually fuse to form several large nearly spherical masses (possibly liposome spheres). The nuclei are crowded to the near edge, and the nuclei are lobulated. There are still some glycogen-like particles with low electron density in the edge of the cytoplasm.