1.6 Electron microscope
According to the published method [29], the above dormant and
non-dormant chlamydospores were coated on cellulose film respectively,
and incubated at 28 ℃ for 12 h, then fixed overnight with 2.5%
glutaraldehyde solution (special for electron microscopy, Beijing
Mycorrhizal Biological Company), and then treated with PBS (0.01 M,
pH7.4) briefly rinsed, alcohol gradient dehydration, tert-butanol vacuum
drying. Samples on the charged rubber were gold-plated fixed, and then
were observed and photographed by using scanning electron microscope
(SEM) (JEOLS-3400IV, Peabody, Massachusetts) under 15 KV voltage.
These dormant and non-dormant chlamydospores were fixed in 2.5%
glutaraldehyde, then washed three times with PBS buffer (pH7.4), placed
in 1% osmic acid for 2 h, and washed three times with PBS buffer. After
gradient dehydration with 30%~90% acetone at room
temperature, the ultrathin sections were prepared by penetration
embedding and polymerization at 60 ℃ for 36 h according to the
conventional process of electron microscopy. The sections were treated
with lead citrate staining solution for 10 min, and then stained with
uranium acetate for 30 min. After washing and drying, JEM-1230
transmission electron microscope (TEM) was used to observe and
photograph.