THE CHLOROPLAST 



87 



found; in the higher plants, chlorophylls a and b occur in a ratio of 

 about 3:1. The number of chlorophyll molecules per chloroplast is 

 of the order of 10"'. The carotenoids, the xanthophylls, particularly 

 lutein and zeaxanthin, and the carotene, ^S-carotene, are intimately 



400 500 600 



WAVE LENGTH IN mp 



700 



Fig. 2. In vivo spectra from two different Euglena chloroplasts taken with 

 the microspectrophotometer (8/x- area). 



associated with chlorophyll in the chloroplast. Other photosynthetic 

 pigments, phycoerythrin and phycocyanin, are present in the red 

 and bliie-green algae. 



In order to analyze more directly the kinds of pigments and their 

 concentrations in a single chloroplast, we have designed and built a 



