Studies on Vernalization and Flowering Substance : I The effects of the extracts obtained from vernalized radish seedlings on the flowering of non-vernalized radish

摘要

Flowering effects of the extracts obtained from vernalized radish seedlings were examined in this experiment, using Raphanus sativus L. var. Minowase as the test plant. The extracts were prepared as the forms of diffusate and juice. The former was obtained by the diffusion of the substances from the germinated radish seeds into the aerated water during the period of vernalization, and the latter was collected from the vernalized radish seedlings grown under the long-day condition (24 hrs. light, 20°C). At the same time, juice from non-vernalized seedlings grown under the same condition was prepared to compare its flowering effect with those of the extracts mentioned above. The extracts were successively applied with Tween 20 to the leaves of non-vernalized radish plants (sown Nov. 27, 1961) from the dicotyledonous stage to the 5th leaf stage almost every day, using a soft brush. The treated radish plants were kept in a growth cabinet conditioned with 24 hrs. light and 20°C. The bolting of the plants in both plots of diffusate and juice-V were noticed in the beginning of Feb. 1962, and finished their flowering by the end of the same month. Whereas, the flowering of the plants treated with juice-NV and Tween 20 only were much delayed until the end of March. The results of the present investigation indicate the existence of the vernalin-like substance in the extracts obtained from vernalized radish seedlings.