vapour fixation

Vapor fixation is one of chemical fixation methods for scanning electron microscope (SEM) observation of mycelia and spores of molds or mushrooms.
When immersed in a fixation solution, mycelia suffer deformation and spores suffer outflow. To avoid these phenomena, the specimen is exposed to the vapor of a fixation solution, and the phospholipids of the biological membranes of the mycelia and spores are fixed. The fixation solution used is an osmium tetroxide solution (concentration: about 2 to 4%). Since the fixation is carried out in the vapor of osmium tetroxide filled in a closed container, several hours to all night are needed for the fixation.