THE ENERGETICS OF PHOTOSYNTHESIS 49 



constants are different the pressure changes are also different. For vessel I 

 we have 



■^02 = ho^Koi -^002 = hco^Kco^ h = /?(>, + hco^ 

 and for vessel II 



Since h and h' are measured, we can derive the following equations from these 

 6 equations with their 6 unknowns 



// K CO, ■" hKco, 



(14) 



K CO, -^coj 



K 02 -^o, 

 and 



_ h K 02 — /'•^02 



J^ O2 _ -^O; (-15) 



CO, ACO2 



From equations 14 and 15 the photosynthetic quotient can easily be calculated 



(16) 



_ ^coj _ K'cOiKcOi h K O; — /?Ao., 

 X02 K'o.,Koi hKcot ~ h K C02 



By writing 



K'co^ ^ ^ 





A' CO, Ar 



= c 



= D 



CO2 •'^002 



we can simplify equations 14 and 15 to the general equations of the two- 

 vessel method 



xo^_ = h'A - hB (17) 



XC02 = h'C - hD (18) 



Fieure 26 shows the arrangement of the vessels in the two-vessel method. 

 Both vessels are illuminated and each contains 7 ml Chlorella suspension. 

 Each non-illuminated vessel contains 7 ml of salt solution and serves as a 

 thermobarometer for the irradiated vessels. The four vessels are connected 

 to manometers, the open arms of which are connected with a two liter flask 

 placed in the same thermostat as the vessels. The four vessels are shaken 



