Abstract
This paper deals with the result of the anatomical investigation on the infection of the anthracnose to cucumber leaves. The resistant and susceptible varieties, Taiwan-Kema and Suyo, were used. On leaves of both varieties. appressoria were formed equally in abundance within 24 hours after the inoculation. In the materials fixed and cut 48 hours after the inoculation, the penetration tube arising from an appressorium was commonly visible, and forced its way into the radial wall of the epidermal cells dissolving the middle lamella. The tip of the penetration tube usually swelled again after it had completed the penetration of the cellulosic wall into the epidermal cell. The chloroplasts of the invaded host cells of both the varieties were collapsed and stained deeply with eosin, when leaves were fixed 94 hours after the inoculation. The macroscopic lesions were formed apparently on leaves 5 days after the inoculation and the invaded host cells collapsed entirely. On both varieties, there was no difference in the thickness of cuticule of leaves and in the morphology of the epidermal cells. The susceptibility in both varieties increased in wounded leaves showing several times the spot number of sound leaves. However, the difference in the spot number between sound and wounded leaves, was equal on both the varieties used. This shows that the wounding gives only a similar number of path ways of the causal fungus to both varieties, and does not remove all the obstacles which resist the pathogenic invasion morphologically.
