Resin fructured surfaces of root nodule of white clover(Trifolium repens L.) infected with Rhizobium trifolii were investigated by a scanning electron microscope.
Nodules which were double fixed with glutaraldehyde and osmium tetroxide were embedded in styrene, and then functured with knife. The fructured specimens were dipped into propy lenoxide. These specimens were transfarred to iso-amyl acetate and critical-point dried using liquid CO_2. The dried nodule tissues were mounted on alminium stages with conductive paste and coated with ion-sputtered gold. Bacteroidal cell of nodule had a developed central vacuole and cytoplasmic area pushed towared the periphery of plant cell wall. In the vacuoles of bacteroidal cells, bacteria were not observable. Bacteria were usually found embedded in cytoplasmic areas, but they were not recoginzed in nuclei of bacteroidal cells. Nuclei and plastids were obseryed, but nuclear envelope and other membrane structures could not visible in the fructured cells.