Effect of Temperature and Nutrients on Flower Initiation of Raphanus sativus L. in Total Darkness

The flowering behavior of Raphanus sativus L. aseptically cultured in total darkness was studied.1. The plants developed flower buds by 120 day cold treatment in total darkness.The flowering response is maximum at 5°treatment, and it decreases with the rising of the treated temperatures from 5 to 25°. At 20-25°the flowering is not observed even after 120 days.2. In dark culture at 5°for 120 days, the plants initiate flower primordia even on plain agar medium. All the substances required for flower initiation in darkness seem to be produced in the seed by cold treatment.3. Plants deprived of cotyledons initiate flower primordia only in the presence of sucrose.4. Light is not necessary for the flowering during or following the thermal treatment; the combination of long days and high temperature is not essential to the initiation of flower primordia.