LOCALIZATION OF THE PYROANTIMONATE-OSMIUM REACTION-PRODUCT IN PLANT-CELL NUCLEOLI

Fixation using a pyroantimonate-osmium mixture has been carried out on plant tissues (Allium cepa roots and anthers). Excellent preservation of the cell ultrastructure was obtained, which made it possible for us to analyze the occurrence and distribution of pyroantimonate reactive sites within nuclei. A preferential location of antimonate deposits was on the fibrillar components of nucleoli, especially in the vicinity of the nucleolus organizing region. These observations have been compared with results obtained previously by other authors in animal cells. The functional significance of the antimonate deposit distribution within nucleoli is briefly discussed. © 1979 Academic Press, Inc.