LIGHT ABSORPTION BY PIGMENTS tn VIVO 



1845 



residual scattering was somewhat stronger with chloroplast-containing 

 algal cells. 



Despite this improvement, the transmission curves, log (Tq/T), ol)- 

 tained by Barer (1955) with the green alga, Chlorella variegata and Scene- 

 desmus ohliquus, were similar to those given by earlier observers, except 

 that transmission was almost constant, or even slowly declining (instead 



400 



500 6 00 



WAVELENGTH- m mu 



700 



Fig. 37C.27. Absorption curves of equivalent quantities of pigments from 

 spinach leaves, in four states. Red band is at 680 m^ on all curves except that 

 for methanol extract (Moss and Loomis 1952). 



of steadily increasing, as in fig. 22.22) between 560 and 620 m^. In fact, 

 the ratios of the optical densities in the green trough and the red peak were 

 even higher than in previous experiments: 0.50 for Scenedesmus, 0.47 for 

 Closiermm, and 0.59 for (green) Chlorella, as compared to 0.28 and 0.33 

 given for Chlorella in table 22.VII. The ratios of the optical densities in 

 the violet and the red peak, were 1.36 for Scenedesmus, 1.59 for Closterium, 



