454 



LIGHT AND LIFE 



Action spectra for enhancement in brown algae and dinoflagellates 

 reflect some active chlorophyll c absorption, though certainly nothing 

 to indicate a role different from chlorophyll b (Haxo, pers. commun. 

 and Blinks, 9) . Since there have been no indications of a photo- 

 synthetic function of chlorophyll d, it is omitted from this discussion. 



Carotenoids 



There is strong absorption by a mixture of carotenoids from about 

 500 xwfji to the near ultraviolet in all photosynthetic plants except for 



u 



c 

 o 



u 

 o 



< 



Chlorophyll o 



( 



Porphyridium 



450 



500 



550 



600 



650 



700 



Wavelcngfh.m^ 



Fig. fi. Absorption spectra of a rctl alga. I'ot jilixridiiim crxicnhuii. a diatom, 

 Koincitld itiiuitua (Siarr No. (>')()), and a green alga, C.lilorclld Tiili^aiis (Starr No. 

 398), to show the absorption bands of varions photosyntiietic pigments. (With 

 G. C. McLeod). 



