766 



Hall, Miller, and Herrero 



Chlorophyll B 



Xanthophyll 



Chlorophyll A 

 Carotene 



Fig. 8. Chronialogiam of the pigment fraction of cotton (1 per cent petroleum ether 

 in n-propanol) and strip count showing major metabolite coincides with carotene. 



Survey of Activity in Cotton Leaves 



Cotton leaves from plants exposed to ethylene-C^^ for 15 hrs. in 

 different experiments were extracted as shown in Figure 7 and the 

 extracts chromatographed in five solvents. At least 18 radioactive me- 

 tabolites were found in the different fractions. It can be noted that con- 

 siderable activity remains in the residue after ether extraction and 

 that approximately two-thirds of the activity is lost tiirough the 

 scheme by heating and hydrolysis. Three radioactive metabolites 

 were foinid in the ether-soluble fraction, the major one being as- 

 sociated with carotene. Eight metabolites were present in the alcohol- 

 soluble fraction, one of which has an amino acid-like structme which 

 will be discussed in detail below. An alcohol-soluble metabolite was 

 found in the sugar fraction but does not appear to be any of the 

 known sugars; the other metabolites soluble in alcohol are probably 

 organic acids. From five to nine radioactive, water-soluble metabolites 

 have been isolated in different experiments. Two of the compoinids 

 containing high a( ti\ ity possess a phosphorus moiety and a tliird com- 

 pound apjjears to be a protein. A( it! or enzyme hydrolysis of the 

 residual tissue shows a number of metabolites associated with tlie 

 cell wall constituents. 



Comparison of the amoinit of C^"* from ethylene fixed in the vari- 

 ous (onijjoncnts of cotton lo the amount of C^' fixed from C^-^Oa in 



