284 M. K. Bach and J. Fcllig 



on a typical chromatogram. The compound having an Rf of 0.5 was 

 eluted and rechromatographed. A single radioactive peak with the 

 same Rf was found. As was reported by Jaworski and Butts (17), 

 refluxing in 2N HCl for 2 hrs. liberated a compound having an Rj 

 similar to that of 2,4-D in the phenol-water and butanol (17) solvent 

 systems. Addition of l-Ci»-2,4-D during the isolation procedure did 

 not give rise to any radioactive peaks on the chromatograms other 

 than that of 2,4-D itself. It must be concluded, therefore, that this 

 material is a compound formed from 2,4-D by the plants. The sug- 

 gestions that this compound is a glycoside (17) or a peptide (9) of 

 2,4-D must be viewed with some doubt, particularly since the band 

 of Rf 0.5 on the chromatograms does contain carbohydrate as well as 

 ninhydrin positive material. These ninhydrin and carbohydrate con- 

 taining bands do not, however, coincide with the radioactive band 

 on rechromatography. 



The Biological Activity of the Product Formed From 2,4-D 



In order to define the time during which the initiation of pro- 

 liferation takes place, it was important to establish whether the 

 compound of Rf 0.5 which is formed from 2,4-D by the bean stem 

 sections has the capacity to induce proliferation, or, indeed, possesses 

 any other biological activity. Table 2 summarizes the results obtained 

 when lO^M concentrations of this material (as calculated from ra- 

 dioactivity) were applied to bean stem sections. The material used 

 had been obtained by mass isolation using the paper chromatography 

 technique described above, and thus contained several nonradio- 

 active contaminants of unknown concentration. Upon rechroma- 

 tography it showed only one radioactive spot (Rf 0.5). It will be seen 

 that this material was completely inactive in causing the proliferation 

 of the bean stems, even though it was applied at ten times the equiva- 

 lent concentration which would be necessary for the maximum ef- 



Table 2. The activity of a crude prepara- 

 tion of the main radioactive product formed by 

 beans from carboxyl-C'''-2,4-D in the bean stem 

 proliferation assay. 



