PHOTOSYNTHETIC PIGMENTS 

 TABLE 3.3 



DISTRIBUTION OF CAROTENOID PIGiMENTS 



29 



Note: In the above table the nomenclature giving a precise 

 chemical indication of the groups present has been given. Thus 

 the ending -ol indicates the presence of hydroxy compounds and 

 luteol, zeaxanthol are preferred to lutein, zeaxanthin, &c. 



Preparation of the leaf carotenoid pigments 



An alcohol or acetone extract of leaves, prepared as des- 

 cribed earlier, contains all the pigments of the chloroplast. 

 The carotenoids are stable to alkali, so that after saponifica- 

 tion, as in the phase test, the carotenoids remain in the ether 

 phase whilst the green pigments pass into the aqueous 

 phase. The pigments are transferred to petrol ether and 

 92% aqueous methyl alcohol added. The carotenes (hydro- 

 carbons) remain in the petrol ether whilst the xanthophylls 

 (having hydroxyl groups) pass into the alcoholic phase. This 

 was the basis of the method used by Willstatter and Stoll. 

 Separation can as previously mentioned be obtained by 

 using a chromatographic technique and later work with this 



