CARBOX DIOXIDE CURVES 



897 



10"^ mole/1, and then abruptly became horizontal (fig. 27. 2C). In this 

 figure the maximum yield corresponds to one volume oxygen per volume of 

 cells each three minutes. The rate values were obtained by admitting a 

 known amount of carbon dioxide into a Warburg vessel, shaking vigor- 

 ously and measuring the pressure changes at short intervals until all carbon 

 dioxide was used up. 



200 







6 31 klux 



.74 klux 



b8-8 — 8- 



0.407 klux 



_i_ 



25 



30 



5 10 15 20 



[C02],in 10'^ mole/ 1. 



Fig. 27.4. Carbon dioxide curves of Cabomba caroliniana 

 (after Smith 1938). 



Figures 27.3 and 27.4, obtained with wheat and with the water plant 

 Cabomba, respectively^ show a more gradual approach to saturation, but 

 they, too, indicate a coincidence of all curves at low [CO2] values, which is 

 characteristic of the Blackman type. Harder's Fontinalis curves (fig. 

 27. 2A), on the other hand, are of a pronounced "Bose type": Curves 

 corresponding to different light intensities diverge from the beginning, and 



