SKOOG AND TSUI 



273 



buds and in all cases markedly retarded the appearance of buds. How- 

 ever, when adenine was supplied together with lAA in the same con- 

 centrations as of each substance above, bud formation was restored, in 

 this experiment, to the same value as in the treatments with adenine 

 alone. These results are in general agreement with the data for tobacco, 

 even though the inherent capacity to form buds was greater and the 



if) 

 "6 25 



UJ 



Q. 



I 



U 



3 



I- 

 o 



HORSE RADISH ROOT TISSUE 



EXP 61 



STARTED 1/12/49 



.Ad.+LA.A. 

 •A<1. 



10 



50 



20 30 40 



TIME IN DAYS 



Figure 6. Effects of treatments with adenine sulfate and lAA on bud 

 formation in horse radish root segments. Exp. #61 started 1/12/49. hiitial 

 pW 4.0; KH2PO4 37.5 mg./l. 



capacity to form roots directly from the original tissue was less in the 

 horse radish. These differences are strikingly correlated with the relative 

 auxin contents of the tissues of the two species (Tables 5 and 6), 



Carrot tissues responded differently. The growth of the original seg- 

 ments, depending on their size and morphological make-up probably 

 as well as on the strain, was either stimulated or inhibited by low con- 

 centrations of lAA in different experiments, and was stimulated by higher 

 concentrations. The highest concentrations (10 to 100 mg./l.) induced 



