200 



CHEMICAL AGENTS AND GROWTH 



90-1 ff -1* 



l35''C;48hr 



50- 



40- 



30- 



20- 



10 



Q 



I- 

 < 



z 



ir 



uj 60- 



o 



50- 



40- 



30 



20 



10 



K G + K 



tT-C.aihr 



n 



G + K 



-|6 _ 



i U n 22°C,40hr 



C G K G* K* 6*+K- 



d 



7°C, 88 hr 



G+K 



Fig. 1. Effects of gibberellic acid and kinetin on germination at dif- 

 ferent temperatures. Seeds in a, c, and d were germinated in darkness; 

 seeds in b were exposed to far-red light during the first 16 hr (see text). 

 Each dotted bar represents one dish of seeds. Solid bars represent average 

 of replicates. Approximately 180 seeds were used per dish in a and b; 

 120 per dish in c and d. It is not intended that comparisons be drawn 

 between experiments at different temperatures. Letters below columns: 

 C, control. G, 3 X IQ-^M gibberellic acid; G*, 3 X 10-«M. K, 5 X 

 lO-^M kinetin; K*, 5 X IQ-'^M. 



concentrations, germination rates were very rapid. Therefore, 3 X 

 lO-'^'M gibberellic acid and 5 X 10" "M kinetin (each 1% of optimal) 

 were used for more accurate evaluation of the effect of gibberellic acid 

 and kinetin in combination (Fig. lb). Whereas either gibberellic acid 



