1963 Volume 76 Issue 904 Pages 351-358
The flowering behavior of Pharbitis nil cultured aseptically under various nutritional conditions was studied. The plants were grown under continuous illumination at a temperature of 15°.
1. Optimal flowering responses were observed when the plants were cultured on sucrose (4-10%) media containing 0.75 or 1% agar and with pH values ranging from 4.32 to 5.50.
2. Minerals of White's solution added to the medium had little influence in causing floral initiation; plants initiated floral primordia on agar medium containing sucrose without minerals. On sucrose media containing 0.05-0.1% KNO3 and Ca(NO3)2, the flowering response was slightly suppressed. However, these media promoted vegetative growth.
3. Glucose, fructose, mannose, maltose, lactose and raffinose gave the same effective results as sucrose in causing floral initiation, but xylose, galactose, mannitol and soluble starch were less effective.
4. Sucrose was effective in promoting floral initiation when applied during the period of low-temperature treatment at 15°, and more effective when applied during the early part than when applied during the late part of the low-temperature period.