著者

山田 保 山崎 恒宜 小川 邦生

出版者

千葉大学

雑誌

千葉大学教育学部研究紀要 (ISSN:05776856)

巻号頁・発行日

vol.16, pp.144-169, 1967-06-30

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The present experiment was carried out in order to clarify the exact nature of hypertrophic causal substance, secreted by the fungus of "witches'-broom", Taphrina cerasi, of the cherry tree. To accomplish this, the authors isolated and purely cultured the fungus. This paper has dealt mainly with the fundmental morphological and cultural properties and products of the fungus. 1. Fungus was collected from specimens obtained from diseased leaves of Primus yedoensis Matsum., at Nishichiba near Tokyo, in April 1964. 2. The fungus was isolated and purely cultured after being suspended in 0.5% CuSo_4 solution for 30 minutes. In all, 10 stocks were obtained. 3. Through the precise experimental procedure applied to the cultural properties of these 10 stocks, they were identified as T. cerasi including a and b strains. 4. It was further found that in the b-strain there are two types, namely, the sporogenesis and the mycelial ; the former propagates, mainly by the division of spores with almost no hyphal development while the latter growsconsiderable hyphae and small numbers of spores are produced laterally to the hyphae. 5. The fungus grew well on potato, synthetic, and cherry leaf-extract media and developed substrate and aerial mycelia. Carbon, phosphate, and potassium were essential elements for the growth of the fungi. 6. Initially the color of a colony was pink, but according to the lapse of the culture duration it changed to black. This constitutes one of the remarkable characteristics of the fungus. That the blackened parts consisted of a considerable number of macrospores constituted another unique characteristic. 7. A close relationship existed between the growth of fungi and the PH-value of the culture medium. In general, a favorable growth was achieved in weak acidity, the optimum being pH 5-6, while no growth was observed at pH 1-2. 8. When a single constituent element was excluded from the basic medium respectively, the growth of fungi became inferior in the order of excluded element as follows : Mg, Fe, N, K, P, and C. 9. No clear zone was observed against Coccus and Bacillus in antagonistic experiments. From this fact it may be concluded that the fungus does not produce any kind of antibiotics. 10. An antagonistic reaction was found to exist between the two strains (a and b) of T. cerasi. This was demonstrated by the fact that a clear zone remained between colonies of a and b strains when grown in proximity on the same medium. 11. Detection of fungous products was carried out using a synthetic fluid medium. The bioassay was applied to the rice seedlings using the lamina joint test, and a substance which proved to be IAA was detected. 12. By chemical procedures the presence of succinic acid and other organic acids were also found in the culture fluid. The authors wish to express their gratitude to Mr. S. Ishida for his cooperation, and to Mr. Harrison R. S. Davis, President of the Japan Christian Junior College, for his kind revision of the manuscript. They are also indebted to Dr. K. Suzuki, Assistant Professor of Chiba University, for his proof-reading.