680 



LIGHT ABSORPTION BY PIGMENTS IN VIVO 



CHAP. 22 



mination with strong parallel light may, however, produce antistrophe in 

 these cells as well. 



Obviously, the effect of parastrophe is to decrease, and that of epis- 

 trophe, antistrophe or diastrophe to increase the absorption of hght. How 



Fig. 22.5. Chloroplasts in Funaria 

 (after Voerkel 1933): above, in liglit 

 (epistrophe) ; below, in darkness (apos- 

 trophe). 



en 

 en 



en 



< 

 a. 



< 



UJ 



o 



130 

 120 



no 



100 

 90 



80 

 70 

 60 

 50 

 40 

 30 

 20 

 10 



20 40 60 

 TIME, min. 



80 



Fig. 22.6. Changes in light 

 transmission through leaves of 

 Tradescantia viridis, caused by 

 chloroplast orientation and 

 starch formation (after Schan- 

 derl and Kaempfert 1933). 



successfully this can be achieved is illustrated by figure 22.5, which shows 

 how Funaria cells change their appearance upon transition from epistrophe 

 to apostrophe. 



Differences in the transmittance of leaves in light of different intensity, 

 caused by the regrouping of chloroplasts, have first been actually observed 

 by Detlefson (1888) and Stahl (1880, 1909). A quantitative investigation 

 was made by Schanderl and Kaempfert (1933); typical results are shown 



