64 PHOTOSYNTHESIS 



suspensions which absorb only part of the incident light a 

 variety of methods of measuring the rate of photosynthesis 

 have been used including manometry', gas analysis, and 

 calorimetric methods. All the results are in good agreement 

 and indicate a value not very different from that obtained 

 for leaves, namely, about 8 to 10 quanta/molecule oxygen. 

 Other observers have avoided the problem of scattered light 



TABLE 4.2 

 EFFICIENCY OF PHOTOSYNTHESIS IN Chlorella pyretioidosa 



IN RED LIGHT 



by using suspensions of algae so dense as to absorb nearly 

 all the incident light. With such suspensions the only 

 measurements have been manometric and have been largely 

 restricted to short alternate periods of light and dark when 

 we are least certain as to the nature of the products of the 

 reaction. Indeed it is clear that the first measurements of 

 Warburg and Negelein (1920), which claimed an observed 

 efficiency in Chlorella pyretioidosa of only 4 quanta/molecule 



