抄録
Pharbitis purpurea Voigt was cultured on Knop's solution whose iron was deficient in various degrees without inducing chlorosis in leaves. Three short-day treatments consisting of 8-hour light and 16-hour dark periods were given about 15 days after the germination, and flowering responses were observed.
1) When iron was deficient throughout the period of plant growth, the effect of short day treatment was decreased with decreasing iron concentration.
2) Iron deficiency preceding the short day treatment gave no influence on the flowering responses, but that during and/or following the short day treatment gave significant influences. The moderate deficiency of iron (5mg./l of FeCl3•6H2O) given during the short day treatment increased flowering response to some extent, but reduced when the same iron-level was continued after the short day treatment.
3) It was considered that the flower initiation was inhibited not by iron deficiency during the period before the short day treatments, but by the iron deficiency after the short day treatment. The moderate iron-deficiency during the short day treatment may accelerate the flowering response.
4) Plants were cultured under iron-deficient condition throughout the total period, and glucose was supplied before, during or after the short day treatment. The glucose promoted flowering response when supplied before or during the short day treatment, but inhibited when supplied after the short day treatment. A remarkable flower-promoting effect of the glucose was obtained under the moderate iron-deficient condition.
