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Govindjee 



of the supplementary light when 700 m\x light is kept constant, 

 and as a function of increasing intensity of far-red light, 

 when the supplementary light is kept constant. Figures 7 and 8 

 show that: (1) With an increase in the intensity of supplement- 

 ary light, the enhancement reaches a plateau and then declines 

 (perhaps we reach the region where the slope of the light curve 

 decreases). (2) With an increase in the intensity of 700 m|a 

 light, the enhancement decreases. Similar results were obtained 

 with 650 and 700 mja light, and with 670 and 700 m|j. light. No 

 enhancement was seen between 690 and 700 mp. at any of the in- 

 tensities used. Due to the use of manometry in the above meas- 

 urements, effects of light on the oxygen uptake could not be 

 avoided. With this in mind, we checked part of our results in 

 Chlorella with a mass spectrometer^^ . Enhancements by factors 

 up to 8-10 could be obtained by selecting the appropriate in- 

 tensity and wavelengths, (650 m|j and 720 m^i) . Enhancement in- 

 creases with an increase in the intensity of 650 m|i light, and 

 decreases with an increase in the intensity of far-red light 

 (at 720 mjj). 



1/14 1/12 l/IO 1/8 1/6 1/4 1/2 



RATIO 700 m>» SUPPLEMENTARY LIGHT ACTIONS 



II 12 13 



RATIO 700 SUPPLEMENTARY LIGHT ACTIONS 



Figure 7. Enhancement effect, in Chlorella, as 

 a function of far-red light intensity. 



Figure 8. Enhancement effect, in Chlorella , as 

 a function of supplementary light Intensity. 



