70 



14 

 mean percentages of the total translocated C-labeled 2,4-D than plants 



which did not receive GA-, pretreatment. No significant differences were 



noted on a dpm/mg basis. 



14 

 An analysis of the cumulative amount of C-labeled 2,4-D translo- 

 cated from treated lamina to plants taken as a whole revealed no 

 apparent significant differences (a=0.05) due to the treatment of 

 waterhyacinths pretreated with gibberellic acid. 



Summary 



14 

 Results of the C-labeled 2,4-D translocation experiments, 



while highly variable, suggest that under growth chamber conditions, 

 pretreatment of waterhyacinths with 100 mg/1 gibberellic acid (1) does 

 not increase the translocation of 2,4-D to men's tematic tissues, and 

 (2) may increase the movement of 2,4-D to previously emerged leaves on a 

 percentage of total radioactivity basis. This suggestion may appear to 

 be somewhat in conflict with other studies which have reported signifi- 

 cant increases in translocation of auxins and/or 2,4-D due to treatment 

 with GA 3 (Ashton, 1959; Basler, 1959; Pilet, 1965; Basler, 1974); 

 however, none of these studies were conducted with rosette species such 

 as waterhyacinths. It is possible, as suggested by Audus (1972), that 

 there may be no interdependence of gibberellins and auxin-like compounds 

 because gibberellins have been shown to produce different responses in 

 different plant species and tissues within the same species. 



