A study was conducted to determine if pretreatment with osmium tetroxide (OsO4) vapor prior to the conventional preparation procedure would increase the retention of fungal structures on leaf surfaces as observed with scanning electron microscopy (SEM). Leaves of black walnut (Juglans nigra L.) were inoculated with conidia of Gnomoma lepfostyla (Fr.) Ces. and de Not., the etiological agent that causes anthracnose of walnut. Following lesion development, leaves were either conventionally prepared with immersion in fixative, ethanol and critical-point dried or vapor-fixed with OsO4 before conventional specimen preparation. Data indicate that significantly more fungal structures were present on OsO4 vapor-fixed leaf samples than on conventionally prepared samples.
Krause, C. R.; Ichida, J. M.; and Dochinger, L. S.
"Osmium Vapor Pretreatment of Gnomonia Infected Leaves,"
Scanning Electron Microscopy: Vol. 1986
, Article 15.
Available at: https://digitalcommons.usu.edu/electron/vol1986/iss3/15