72G 



LIGHT ABSORPTION BY PIGMENTS IN VIVO 



CHAP. 22 



itself, could be recognized in the spectrum of a bile salt extract and ap- 

 peared to be shifted by about the same amount— 15 m/x.) We know, how- 

 ever, that the blue-violet band of chlorophyll is shifted by approximately 

 the same amount as the red band on the frequency scale (and not on the 

 wave length scale), and the bands of the carotenoids— particularly those of 



1 — [—1 — I — r— 1 — I — I — I — r— r- 



T— I — I — r— I — 1 — I — I — I I I — I — I I I I I 



Chlorophyll o 

 Total carotenoids 



Fucoxanthol 



Caretenoids other 

 than fucoxanthol 



400 



500 600 



WAVE LENGTH, m/i 



700 



Fig. 22.46. Distriliution of alisorption in acetone extracts from Nitzschia 

 closterium (after Button and Manning 1941). Lowest curve, chlorophyll a. 

 Middle curve, chlorophyll a + carotenoids other than fucoxanthol. Top 

 curve, all pigments. 



fucoxanthol— probably are shifted much further than those of chlorophyll. 

 Thus, figure 22.46 must contain considerable errors. The absorption by 

 fucoxanthol above 500 m/x probably is much stronger than shown, with 

 the consequent increase in general absorption in this region. (Figure 22.46 

 represents a green rather than a brown mixture!) 



