617 



Mordhay Avron and Noun Shavit 



Table 1 

 The effect of osmotic concentration on the rate of photoreduction of 



ferri cyanide 



Details as described under Fig, 1, except that the only reaction components 

 present, other than chloroplasts are indicated in the table. The numbers in 

 parantheses refer to concentration in ^moles per ml. 



several photoreactions of chloroplasts was interpreted as pointing to two separate sites of 

 ATP production in chloroplasts. The large changes in the extent of inhibition of several 

 photoreactions by uncouplers and other inhibitors as the light intensity was changed was 

 illustrated. Finally, an osmotic concentration effect was described which largely determines 

 the rate of electron flow in several photoreactions. 



Acknowledgements 



The research reported in this document has been supported, in part, by the Air Force 

 Office of Scientific Research, OAR, through the European Office, Aerospace Research, 

 United States Air Force, and, in part, by a grant from the C.F. Kettering Foundation. 

 We wish to thank Dr. P.O. Heytler of the du-Pont Co., Wilmington, Delaware, for the 

 samples of p-CF^O-CCP and DCMU, and Mrs. F. Itshak for excellent technical 

 assistance. 



