134 Fundamentals of Auxin Action 



seem to be common results following applications of large amounts of 

 auxins. 



Here again the role of reducing sugars is distinctive. Although 

 treatment of plants with strong auxin applications may lead to an 

 ultimate depletion of carbohydrate reserves, still there is frequently a 

 large rise in the reducing sugar content. This can be readily seen in 

 the data of Rasmussen (1947) concerning the effects of 2,4-D on dande- 

 lion root composition given in figure 61. 



25 DAYS 



TIME AFTER TREATMENT 



Fig. 61. Changes in chemical composition of dandelion roots after treatment with 

 480 mg./l. of 2,4-D (from Rasmussen, 1947). 



The changes in nitrogenous constituents of plants are not even as 

 well understood as are the carbohydrate changes. Under some circum- 

 stances large increases in nitrogen content have been observed after 

 treatment (Wort, 1949) and in other cases pronounced decreases are 

 found instead (Rhodes et al, 1950). Using plants supplied with differ- 

 ent levels of nitrogen. Wolf et al (1950) found that bean plants 

 grown with low concentration of nitrogen showed not only much less 



