86 



The Quantum Efficiency of Photosynthesis 



No. 5 

 5 'white— 18.5mm 5 '(white + red) + 22.0mm 

 5'white-; 18.0mm 5 '(white + red) + 22.5mm 

 5 'white— 16.5mm 5 '(white — red) + 22.0mm 

 5'white — 17.5mm 5 '(white + red) + 20.5mm 

 5'white- 17.0mm 5 '(white + red) + 23.0mm 



25'white + 87.5mm 25'( white + red) + 110 mm 



No. 3 



5'white + 14.0mm 5 '(white + red) - 15.0mm 



5'white — 14.0mm 5'( white — red) — 16.5mm 



5'white + 12.5mm 5 '(white ; red) — 16.5mm 



5'white -1- 14.0mm 5 '(white + red) + 14.0mm 



5'white + 11.5mm 5 '(white + red) + 15.0mm 



5'white + 12.0mm 5 '(white ! red) + 14.5mm 



25':H' = 110 -87.5 



22.5 mm 



30 ' white + 78 mm 30 '( white -| 

 30:H = 91.5 — 78 - + 13.5 

 25':H = 11.3 mm 



red) 

 mm 



91.5mm 



Calculation of quantum efficiency for experiment I (Dark ± Red) 



In 60': H + 31.5 mm H' + 59 mm 

 Applying equations (1) and (2), protocol (1) 



In 60'xoo + 70.4 /d | CO2 



xco 2 = — 56.0 //l 



Quantum efficiency for O2, 



Quantum efficiency for CO2, 



0,8 



4.6 



5.8 



q> 56 



Calculation of quantum efficiency for experiment II (White ± Red) 



In 25':H i 11.3 mm H' f 22.5 mm 

 Applying equations (1) and (2), protocol (I) 



In 25' xo 2 



XCO-2 



30.3 ,/d \ 

 27.2 /d | 



Quantum efficiency for O2, 

 Quantum efficiency for CO-j 



V 





CQ 2 



Oo 



25 



0.90 



5.4 



30.3 

 25- 5.4 



27 



4.5 



5.0 



Experiment III, with the same cells, was performed between experiments I and II, the white 

 light being, however, of somewhat lower intensity. Here only one vessel (No. 5) was used; but if we 

 take as y the average value of experiments I and II, that is — 0.85, xo 2 can be calculated according 

 to equation (3), protocol (1). The readings in vessel (5) were: 



red) + 

 red) + 

 red) + 

 red) + 

 red) + 



11.5 mm 



9.5 mm 



9.5 mm 



13.0 mm 



15.0 mm 



and with y 



0.85 



25' white + 30.5 mm 25'(white + red) + 58.5 mm 

 25':H' == 58.5 — 30.5 = + 28 mm 



25' xo, = + 34 /d 



The quantum efficiency with the actinometer value of experiments I and II (5.4 /d O2 per 

 minute) was 





25 • 5.4 

 34 



= 4.0 for O2 



The total duration of these experiments was 7 hours from the time of initial equilibration until 



1 

 the last yield determination that gave a value — 4.5 for oxygen, which was obtained at approxi- 



mately 4 times the compensation point. The final pH in the cell suspensions was 5.4. 



