22 

 study discussed above which either suggested or investigated a possible 

 mechanism for GA2~enhanced translocation of auxin compounds was that of 

 Basler (1974). Utilizing cycloheximide, a protein synthesis inhibitor, 

 it was shown that continuous protein synthesis was needed to maintain 

 high rates of 2,4,5-T translocation in bean seedlings. The simultaneous 

 treatment of 2,4,5-T, GA 3 and cyclohexamide negated the enhancement of 

 translocation of 2,4,5-T by GA3. In an unrelated study utilizing corn 

 ( Zea mays ) seedlings, which does however demonstrate the interrela- 

 tionship of various plant growth substances, synergism was demonstrated 

 between GA3 and fluridone, a herbicide which blocks carotenoid synthesis 

 (Devlin et al . , 1980). The exact mechanism of synergism was unknown; 

 however, Devlin et al . (1980) suggested that since cartenoids are pre- 

 cursors of abscisic acid (ABA) and since ABA and GA had been shown to be 

 mutally antagonistic (Corcoran, 1974), reduced ABA levels caused by 

 the absence of carotenoids might allow greater expression of 

 GA 3 activity. 



Audus (1972) summarized the interaction of plant hormones by stating 

 that there may be no underlying interdependence of gibberellins and 

 auxin-like compounds because (1) gibberellins will produce different 

 metabolic responses in different tissues, and (2) growth or develop- 

 mental process may be subject to the regulatory action of a balance of 

 several hormones whose points of action may be quite independent but 

 appear to interact due to the mutual association of each component to 

 the total growth system of a given species. 



Commercial Applications 



The numerous physiological and morphological effects of gibberellins 

 have led to investigations into potential commercial uses. Initial 



