PHOTOSYNTHETIC PIGMENTS 



23 



Properties of chlorophyll in solution 



I . Absorption of light. On a molecular basis the absorp- 

 tion of light by chlorophyll is very high, being for example 

 three times greater than that of the chemically related pig- 

 ment, haemoglobin, in the visible region. In solution both 



r 



180 



% 



SO 



.C 



8 



.0 



■io 

 so 

 .<o 



I 



400 SOD 600 660 



Wavelength of light . 



FIG. 3.3. Absorption curves of chlorophyll a^ (■ 



mf 



-) and 



chlorophyll 6( )in ethyl ether. (Data of Zscheile and 



Comar.) 



chlorophylls show absorption spectra of a similar type char- 

 acterized by a very strong band in the red and one in the 

 violet. In ether chlorophyll a appears green-blue, while 

 chlorophyll 6 is a more yellowish green. In a thick layer (or in 

 high concentration) solutions of both chlorophylls transmit 

 only red light. At the red end of the spectrum the maximum 



