1058 



THE LIGHT FACTOR. I. INTENSITY 



CHAP. 28 



2 3 4 5 

 TIME, min. 



2 4 6 8 10 12 14 

 TIME, min. 



5 6 7 8 9 10 20 

 TIME, min. 



Fig. 28.37. Effect of low temperature on steadj' state 

 fluorescence at various light intensities (after Franck, 

 French and Puck 1941). 



10 20 30 40 50 60 70 80 90 100 110 120 130 

 LIGHT INTENSITY, 10"^ erg/cm^ sec 



Fig. 28.38. Fluorescence yield as function of intensity of exciting light 

 at room temperature, and at 0° C, where photosynthesis is inhibited 

 (after Franck, French and Fuck 1941). 



