744 



Constantine Sorokin 







2 3 

 HOURS 



Fig. 2— Rates of photosynthetic gas exchange (in 

 relative units) for lO-min. intervals in synchronized 

 0- and 8-hour cells of Chlorella ('5), 



growth ^*°f have been also reported to decline toward the end of 

 the life cycle. Available information on nitrogen accumula- 

 tion (20), nucleic acid content (21), ash constituents (22)^ 

 phosphorvlation activity (23), and contents of several vita- 

 mins (2^) also indicates that all these variables depend on the 

 developmental status of cells. 



Surprisingly, observations on the dependence of metabolic 

 activity on the developmental status of cells have made small 

 impact on studies of metabolism, and particularly on studies of 

 photosynthesis. A plausible explanation for the little con- 

 sideration given to the developmental aspect of photosynthesis 



