102 



Chemical Control of Flowering 



Fig. 6-1. Substitution of gibberellic acid (GA) for cold treatment in the flower- 

 ing of the biennial, carrot (Daucus carota). Left to right: controls on long days only; 

 long days plus GA, no cold treatment ; long days plus previous cold treatment, 

 no GA. (Photograph from Lang [1957], courtesy of Dr. A. Lang, California 

 Institute of Technology.) 



