Long-Day Flowering of Perilla Plants Cultured in Nitrogen-Poor Media

Green-leaved and red-leaved Perilla plants (short-day plants)cultured aseptically on diluted modified White's medium or onfull strength White's medium (W) containing reduced concentrationsof nitrogen sources, initiated flower buds under continuouslight (2,000–2,200 lux fluorescent lamps) at 24–26?C.The addition of sucrose to the medium promoted flower formation;the optimum concentration was 2% in 1/10?W medium. The plantscultured on unfertilized vermiculite also developed flower budsreadily, unlike those on fertilized vermiculite. High-intensity light (8,000 lux fluorescent lamps) given duringthe first 30 days of culture promoted flowering. This effectwas also produced to a lesser degree by the addition of sucroseto the medium, instead. On the other hand, high-intensity lightgiven during the second 30 days or throughout the culture periodinhibited flowering, irrespective of the presence of sucrosein the medium. (Received February 4, 1982; Accepted June 14, 1982)