Ultra-structure of Leaf-gall of Symplocos lucida Sieb. et Zucc. Caused by Exobasidium symploci-japonicae Kusano et Tokub.

Ultra-thin sections of the hypertrophied leaf-tissue of Symplocos lucida Sieb. et Zucc. infected with Exobasidium symploci-japonicae Kusano et Tokub. were investigated by means of an electron-microscorpe. In the hypertrophied tissue, pathogens were recognized in inter-cellular spaces (Figs. 5, 6, 7), middle lamella (Figs. 1, 2, 4) Cell wall and cell membrane was invaginated (Fig. 3) but pathogen was not observed in the suscept cell. As shown Figs. 2 and 4, lomasome like structures were observed in the hyphal cell but other organelles were not found in the fine hypha.The writers considered that hypertrophy of Symplocos lucida occurred earlier than the invagination of the suscept cell wall by the pathogen. Hypertrophied cell had a large vacuole (V) and thin peripheral layer of cytoplasm. Sometimes, high electrondense material was recognized in the vacuole of the hypertrophied cell (Fig. 7). Plasmolysis was not observed in the suscept cell. Lamellar structures, osmiophilic granules and starch grains were found but grana structures were not developed in the chloroplasts of the hypertrophied cell (Figs. 8, 9, 10). Occasionally, nucleus had two nucleoli (Fig. 6).