132 



Barlow, Hancock, and Lacey 



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Fig. 3. Growth (as a percentage of controls in water) of wheat leaf bases in various 

 combinations of sodium indole-3-acetate and gibberellic acid in the presence or 

 absence of the inhibitor. The shaded portion represents the reduction in growth 

 due to the inhibitor (5 ints/ml). 



and five sections put into small vials with 0.2 ml. solution. As in oin- 

 coleoptile section test, these tubes were rotated horizontally for the 

 growth period of ca. 20 hrs. (though a longer period is probably ad- 

 vantageous in this test) . Mixtures of NalAA and GA (gibberellic 

 acid) were used with and without inhibitor at a concentration of 

 5 ints/ml. Figure 3 shows the results, from which it is clear that the 

 inhibitor reduces leaf extension in all solutions about equally — it is 

 not only the lAA-induced growth which is aflected. 



Slit Pea Stem Curvature 



Sections 4 cm. long were cut from the third internode of 'Alaska' 

 pea seedlings grown in the dark with short daily doses of white light 



