1957 Volume 26 Issue 1 Pages 1-8
1. Short day and lower night temperature favor the pistillate flower formation of the cucumber plant, and on the contrary, long day and higher night temperature favor the staminate flower formation.
2. In this report, the cucumber plant was set under the changed day length and night temperature during the various stages of the plant growth in the nursery bed, for the purpose of detecting the responding ranges of the plant portion, influenced by the adverse conditiont at the respective stages.
3. The respective 10 days sequence of the growth period of the plant in the nursery bed is denominatod as I-, II-, III-and IV-period.
4. The response reveals itself at the higher nodal successions as compared with the histological survey of the floral primordia. It seems that the physiological changes brought about by the influence of the day length and night temperature precede the formative effect.
5. When short day and lower night temperature prevailed during the II-III period of the plant growth, the antagonistic influence of the long day or higher night temperature during the IV-period failed to balance the preceding treatment. The effect of the short day and lower night temperature prevailed only during the III-period of the plant growth, was fairly balanced by the antagonistic influence of the IV-period treatment.
6. It seems that the day length and the night temperature affect the physiological condition of the plant according to the duration period of the treatment. The physiological conditions in its turn influence the sex determination of the successively developing flowers.
7. Practically, the most careful control of the suitable day length and night temperature is needed during the II-III periods.