216 



H. TAMIYA, S. iMIYACIIl, T. IIIIU)KA\\ A 



TIME IN MINUTES 



Fig. 5. Effect of O, on the decay of R in the dark. Temperature: 20 °C. 

 Abscissa: the time which the cells spent in the light and dark, and in N2 and O2, 

 as indicated, prior to the provision of C^''02. 



- LIGHT 



QUINONE ADDED 



V NONE 



40 GO 60 



TIME IN MINUTES 



ion 



Fig. 6. Effect (in the light) of varjnng concentrations of quinone on the i?-level 

 which had previously attained the stationary value in the absence of quinone. 



acteristic second transient) was not affected by oxygen but the final 

 R level was less in air than in N2. If R was formed anaerobically and 

 the suspension later flushed with air the same final steady-state value 

 of R was obtained as shown by Fig. 3. The effect of oxygen in depress- 



