Abstract: The infection processes of Colletotrichum gloeosporioides and activities of chitinase and β-1,3-glucanase in leaves of Cymbidium sinense were studied after inoculating C. gloeosporioides. The results showed that the stomatic cavities in the epicuticula of leaves of C. sinense were infected by the hyphae of C. gloeosporioides at 12 h after inoculation. Both of the primary and secondary hyphae of C. g loeosporioides extended and developed in the intercellular spaces of mesophyll tissues in 36 - 60 h after inoculation. The cytoplasms were
infected at 84 h, and disintegrated partly. The activities of chitinase and β-1,3-glucanase increased inoculated with C. gloeosporioide. Both enzymes activities reached the highest level at 84 h. Therefore, the results suggest the importance of hyphae successfully infecting intercellular spaces and cytoplasm of mesophyll tissues in leaves of C. sinense as the occurrences of active peaks of chitinase and β-1,3-glucanase.

Key words: Cymbidium sinense, Colletotrichum gloeosporioide, Infection, Chitinase, β-1, 3-glucanase