Fig. 1. Placement of solution on the vegetative apex for assay of gibberellin in the 

 bean epicotyl elongation test. 



Table 2. Comparative biological activities of gibberellins Ai, Ai, A3, and A4 (ex- 

 pressed as per cent of control). 



* Two ml. of a 100 p. p.m. solution per 6-cm. petri dish. 



