729 



Williatn Vidaver 



lOOOpsi 



I 



12 3 12 



Time.min 



Fig, 2. Induction time courses of oxygen evolution at 

 three different hydrostatic pressures. Intensity of 

 white light was approximately one-half that required for 

 steady rate saturation. No pre-a transient (described 

 in text) is visible in the response of the marine algae 

 (a,b,c). A distinct transient appears on the rise of 

 the a spike in Ankistrodesmus (d). While steady rates 

 were affected more by pressure than maximum a spike 

 rates, the pre-a transient is least inhibited (15°). 



