Physiological and Anatomical Effects 133 



hydrolysis of the starches, but is probably a result of the assimilation 

 of carbohydrates from the culture mediiuii. 



Studies of the heri)icidal activities of stronger treatments witii 

 plant growth regulatois ha\e tlarified some of the dianges in plain 

 constituents after auxin applications. Sell et al (1949) demonstrated 

 gross changes in carbohydrate and nitrogenous constituents following 

 the application of large amounts of 2,4-D to bean leaves. Some of the 

 most striking changes were found in the stems. The 2,4-D caused a 

 rapid decrease in carbohydrate content of stems including reducing 

 sugars, non-reducing sugars, and starch dextrins (see table 7). The 



TABLE 7 



Changes in Constituents of Stems of Red Kidney Bean Treated with 2,4-D 

 (One Drop of 1000 p. p.m. Applied at Base of Blade of Primary Leaf) as Com- 

 pared WITH an Untreated Control. Data Expressed on a Lipid-Free Dry Weigh r 

 Basis. 



(Sell el al, 1949) 



depletion of the carbohydrate fractions was associated with an ap- 

 parent increase in protein and amino acid fractions. The overall 

 protein content was almost doubled and many of the specific amino 

 acids measured were, in fact, more than double those in the controls. 

 Furthermore, substantial increases in the ash content were observed 

 and increases in several of the pigments. It should be recognized that 

 data such as these may be complicated by the fact that the actual dry 

 weight of the plant material is reduced as a result of the treatment and 

 consequently expressing plant constituents as a percentage of the 

 control per unit dry weight can be somewhat misleading (Klingman 

 and Ahlgren, 1951). However, the general trends of disappearance of 

 carboliydrate fractions and accumulation of nitrogenous materials 



