2.1 Observation and staining of different types of
chlamydospores under general light microscope
Under an optical microscope, the dormant or non-dormant chlamydospore
appears round or oval and yellowish brown in the absence of staining
(Figure 1A & 1B), while the staining of artificially killed spores were
dark (Figure 1C). The normal mature chlamydospore was double walled,
spherical, 11.3~35 μm in diameter, and oval in size
16.3~27.5×27.5~67.5 μm. The average
spore wall thickness under oil microscope was 2±0.1 μm. The immature
chlamydospore or the spore in liquid medium has a smooth surface and has
globular protuberances on the surface when mature. The above three types
of spores can be stained blue by lactol cotton orchid staining (Figure
1D, 1E & 1F). The artificially killed spores were pale and dark in
color. The three types of spores stained with trypan blue were all black
(Figure 1G, 1H & 1I), is difficult to distinguish. In MTT assay,
dormant and non-dormant spores were stained black or blue, and no matter
the spores died artificially or naturally, they were not stained (Figure
1 J, 1K, 1L & 1M). Their differences were significant, suggesting that
this staining method could distinguish dead and dormant
spores.