4IC 



11. A. OLSON. F. 8. BHACKKTT, R. G. CRICKARD 



ever, when the cells are observed under limiting CO2 pressure (i.e., 

 eorresponding to less than 0.5%), one observes sharp initial bursts 

 such as shown in Y'lg. 4. However, these appear not because of en- 

 hancement but because of the reduction in the subsequent sustained 



5 10 



TIME IN MINUTE INTERVALS 



15 



Fig. 5. Comparison of rate burst at high and low CO2 concentration after dark 

 adaptation for over 2 hours. Tracings of slope records: (B) equilibrated with air 

 (0.03% CO2); (A) (displaced) equilibrated with 5% CO2 in air (normal gain). 



rate. Thus as shoAvn in Fig. 5,* comparing high and low CO2, the sus- 

 tained value is higher than the burst. 



On closer examination, evidence of the burst is still found at the 

 higher nonlimiting level of CO2. This resolution of the burst from the 

 subsequent sustained rate is partly due in this case to induction pro- 

 duced by several hours of dark conditioning. Of particular interest is 



* Original records are shown wherever possible but tracings are used whenever 

 intercomparison of two or more records is required. 



