PART 2 - TRANSLOCATION EVALUATIONS 



Introduction 

 Various studies have shown increases in rates and amounts of 

 translocation of radioactive labeled auxins and 2,4-D when plants 

 were pretreated with GA (Ashton, 1959; Basler, 1959; Pilet, 1965; 

 Basler, 1974). The studies utilized either whole, immature plants or 

 stem segments of bean plants. Singh and Muller (1979b) reported that 

 asulam and amitrole have higher rates of translocation in waterhyacinths 

 than 2,4-D, and this may be the reason they are more efficacious against 

 waterhyacinths. Pieterse et al . (1980) and Pieterse and Roorda (1982) 

 suggested that increased translocation was the mechanism by which 

 waterhyacinths exhibited a ten- fold increase in sensitivity to 2,4-D 

 when also treated with GA. The objective of this portion of the 

 overall investigation was to determine if increased translocation of 

 2,4-D in waterhyacinths was the mode of action of increased sensitivity 

 of waterhyacinths to 2,4-D when also treated with gibberellic acid. 



Materials and Methods 

 Waterhyacinths for this study were collected from a small tributary 

 stream of the St. Johns River in Jacksonville, Florida. Plants were 

 selected for uniformity of size (approximately seven leaf stage) 

 and apparent freedom from disease and insect damage. All plants were 

 allowed to remain in the growth chamber for 3 days prior to treatment. 



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