Hormones and hormone precursors 



separation was achieved. Peaks of activity were obtained at R. 0- 1-0-3 

 (zone X), Rf 04-0-6 (zone Y), and R^ 0- 7-0-9 (zone Z). Stimulation at Z 

 was greater than with 1 -0 mg/1. lAA. Stimulation at X, which closelv 

 followed the lAA control, could be associated with a pale blue and purple 

 fluorescence. Zone Y had a pale pink fluorescence and zone Z no fluores- 

 cence. With the colour sprays no reactions similar to those of lAA and IAN 

 could be obtained. 



This experiment was repeated several times, with the same results. It was 

 decided to try to isolate these three peaks to study their behaviour and to 

 determine any relationships between them. 



Response to lAA 

 (mg/l.) 



t 



I 



lAA 



IAN 



(b) 



H.O — 



J L 



J L 



Response foIAA 

 (mg/V) 



Response to lAA 

 (rag/l.) 



OS 0-f 0-6 0-8 



1-0 



Figure 5. [a) Aqueous fraction of excised roots developed in ammoniacal n-butanol. (b) ^otie X of 

 aqueous fraction developed in ammoniacal n-butanol. (c) ^one Y of aqueous fraction developed in 

 ammoniacal n-butanol. 



Two further chromatograms, each loaded with one-tenth of the aqueous 

 fraction, were developed in the same tank. One chromatogram was bio- 

 assayed to locate zones X, Y, and Z (Figure 5(a)). The zones of the second 

 chromatogram corresponding to A' and Y were re-chromatographed in 

 «-butanol/ammonia (Figures 5(b) and (c) respectively). 



In each case the running of zone A' or zone Y had produced three peaks. 

 A pale purple fluorescence was obtained at zone Z in each chromatogram. 

 It is possible that separation of A^ and Y may not have been complete before 

 re-chromatography. However, it is clear that Z was formed from either X 

 or Y , though it is not possible to state which of the two zones was responsible. 

 It would appear that A' and Y are interconvertible, behaving like tautomers 



47 



