Abstract
Ultra-structure of the hypertrophied leaf-tissue of Camellia sasanqua Thunb. infected with Exobasidium gracile (Shirai) Sydow was observed by means of an electron-microscope. The results were shown in Figs. 1-13. Hyphae (H) were recognized in intercellular space (Figs. 3, 4), middle lamella (Figs. 5, 6, 9), cell wall (Figs. 7, 8) and on the surface (Figs. 1, 2) of the suscept tissue. As shown in Figs. 1 and 2, nucleus, nucleolus, vacuole and lipid-granules were observed in hyphal cell but those organelles were not found clearly in fine filamentous hyphae (Figs. 3-6). Cell wall and cytoplasmic layer of the suscept cell were invaginated (Figs. 7, 8) but haustorial structure was not observed. The writers considered that hypertrophy was caused by the pathogen before the invagination of the suscept cell wall. Low electron-dense substance was observed in the surrounding part of the hyphae in the suscept tissue (Figs. 1-4). Hypertrophied cell had a large vacuole (V) and thin peripheral layer of cytoplasm (Figs. 3-11) as shown in Fig. 10.
Sometimes, high electron-dense material was recognized in vacuole of the suscept cell (Figs. 5, 6, 9, 11). Lamellar structures and osmiophilic granules were found but starch grains were not observed in the chloroplasts of the hypertrophied cell (Figs. 3, 4, 12, 13). Plasmolysis was not occured and cell membrane was adjacent to the cell wall of the suscept.
