102 



PHOTOCONTROL OF GROWTH 



Fig. 1. The response of Salvia occidentalis to a long-day treatment in 

 colored light. From left to right: plants grown in red, green, blue, and 

 blue + infrared light, 16 hr per day, 900 ixw/cm-, 56 days after the 

 beginning of the treatment. 



light, however, no long-day effect was obtained at all, and thus flower- 

 ing was not prevented (Fig. 1). 



In other experiments in which unequal intensities but equal amounts 

 of light quanta were given, it was found that red light was less effective 

 than blue (the flower induction was retarded but not prevented) (Ta- 

 bles I and II). 



Table I. Response of Salvia occidentalis to a Short-Day and a Long-Day Treat- 

 ment in Different Spectral Regions (Equal Amounts of Light Quanta) (Duration of 

 treatment, 32 days; day temperature, 22°C; night temperature, 17°C) 



