616 



A. W. Galston and D. C. McCune 



Table 4. GA-IAA synergism in green pea stem sections pretreated with GA for 1 

 hr. and later exposed to lAA. 



GA and lAA "pulses" are not important in determining either the 

 growth or degree of synergistic interaction. 



In summary, it appears that GA-IAA synergism is not demon- 

 strable in etiolated tissue, but shows up in appropriately treated green 

 tissue. The factors that enhance the synergism in green tissue seem 

 to be short duration of daily illumination and possibly passage of 

 GA through a considerable length of stem. 



THE EFFECTS OF GA ON PEROXIDASES IN 

 DWARF PEAS AND CORN 



Several previous investigators have reported that dwarf plants 

 in such widely divergent genera as Phaseolus, Epilobium, Zea, and 

 Pisum have much greater peroxidase activity than their normal coun- 

 terparts (8, 12,20,23). In view of the fact that GA is known to alter 

 the phenotype of certain dwarfs to normal (1, 17), it seemed im- 

 portant to discover whether the peroxidase activity of such GA-treated 

 plants was also altered to the normal pattern. The plants used in these 

 investigations were dwarf peas, 'Progress No. 9' and tall peas, 'Alaska,' 

 both obtained from Associated Seed Growers, and a segregating popu- 

 lation of corn, yielding 75 per cent tall plants and 25 per cent dwarf- 1 



Table 5. Effect of duration of pretreatment with 10 '' M GA on degree of syner- 

 gism with lAA in green pea sections derived from 8 hr. photoperiod plants. 



