Abstract
1. In the previous report, the effect of the varied day length and night temperature of two or four days duration upon the sex pattern of the cucumber plant was studied. It is observed that long day and high night temperature of even such short duration influenced the physiological state around the floral primordia just going to differen-tiate sexually. Although recovering gradually by the oppositional effect of the prevailing day length and night temperature., these temporarily affected condition seemed to stand rather long even under the day length and night temperature kept to favor the pistillate flower formation.
2. In this report, α-naphthaleneacetic acid (10ppm solution) was sprayed for the purpose of indu-cing the pistillate flower against the long day and high night temperature treatment which favored to induce the masculating condition. In the fore-going report, it is shown by the authors that α-naphthalenacetic acid spray of 10ppm solution induces the pistillate flower formation.
3. α-naphthaleneacetic acid applied at the second period of the seedling development induced the first pistillate flower on the fourth node of the main stem against the prevailing long day and high night temperature. Later application. of α-naphthaleneacetic acid spray induces later-differentiation of the first pistillate flower on the main stem.
4. Following α-naphthale neacetic acid applicat-ion, even on the staminate nodes just beneath the induced pstillate flower node, on which already one-or more ordinary staminate flowers had opened, there bloomed the induced pistillate flowers. The-sex of the floral primordia of the staminate nodes. are reversed by α-naphthaleneacetic acid spray.
5. It is observed that by means of α-naphtha-leneacetic acid spray the pistillate flower differen-tiation is induced even against the adverse day length and night temperature. The effect of α-naphthaleneacetic acid appears so soon but it en-dures not so long against the adverse conditions.
