1. In other papers, the writers divided the pathogenicities of culture-strains of the rice blast fungus,
Piricularia Oryzae BR. et CAV., into three classes. According to SATOH (6) and SETO (7), the rice blast fungus is capable of decomposing the cellulose added to the culture media. In the present investigation the writer has intended to compare the degree of such abilities shown by 21 culture-strains of the fungus and also to illustrate the relation. between their pathogenicities and cellulose-decomposing abilities.
2. The writer cultured those strains on the synthetic agar plates containing colloidal cellulose for two weeks. The cellulose-decom-posing abilities of the strains were compared by means of measuring the width of the clear and semitransparent zones appeared around the developed colonies of the fungus, when iodine-solution was poured on the plates.
3. As far as the writer's experiment was concerned, the cellulose-decomposing abilities shown by those culture-strains were obviously differentiated. Such strains, as No.3, 9, 10, 12, 15, 20, 21, 29 and 34, showed the most active ability, while those, as No.17, 25 and 32, were the weakest. The other strains were inserted between the above two groups, although there were some variations among them. Such specialization in the cellulose-decomposing abilities of the fungus seemed to be almost parallel to that in their pathogenicities. The strains, which were strong in the pathogenicity, showed generally the active ability in the cellulose-decomposition.
View full abstract