Inhibition of Gibberellin Action by Auxin 663 



Dr. Brian: 1 would like to add that the test that Miss Radley uses 

 is basically similar to this, although the plants are cut above the node 

 and wheat is used instead of oats. Certainly we have never encoun- 

 tered any inhibition by lAA as you have suggested. We do regard 

 it as an almost specific test for gibberellins, but occasionally we find 

 that there is a response in leaf extension due to auxin. Although we 

 use this technicjue in our work on screening for natural gibberellins, 

 we always confirm the results by using one of the tests involving a 

 genetic dwarf. 



