1. S. Mizusaki, Y. Tanabe, M. Noguchi and E. Tamaoki, Abstracts of Papers, The Annual Meeting and The Symposium of Japanese Society of Plant Physiologists, Okayama, April 3, 1972, p. 91.
2. M. Takahashi and Y. Yamada, Abstracts of Papers, The Third Symposium for Plant Tissue Culture, Nagoya, July 28, 1972, p. 71.
3. D. Yoshida, Bulletin of The Hatano Tabacco Experiment Station, No. 54, September, 1964, p. 20.