MONOCHROMATIC LIGHT CURVES 



1159 



how completely the "quantized" light curves obtained in monochromatic 

 light of different color coincide in their initial sections is given in figure 30.5. 

 Although the two uppermost points in this figure fall into the region of 

 beginning saturation, they still show no difference between the liglit curves 

 in green and red light. However, a divergence of these two curves in the 



NT 



E 



O 



in 



7 - 



.E 5h 



E 



O 



_» 

 O 



E 



(O 



V) 

 UJ 



X 



I- 

 z 

 >- 

 to 

 o 

 I- 

 o 



X 



a. 



Fig. 30.5. 



4 - 



3 - 



2 - 



J 123456789 10 



INTENSITY, einstein/cm^min, x 10' 



Photos\-nthesis of Chlorella as function of intensity at three 

 wave lengths (after Emerson and Lewis 1943). 



Nf,j (absorbed) 



N^^ (incident) 



Fig. 30.6. Expected shapes of monochromatic light cm-ves. (A) P vs. Nt,„ for 

 total absorption, A^^^, (absorbed) = A^^^, (incident). (B) Same for incomplete 

 absorption, Nn;, (absorbed) < N^y (incident). (C) For equal absorption, equal 

 quantum yields but different wave lengths; the curves in (C) would coincide if 

 Nh:, were used as abscissa instead of /. In (C), the unbroken curve is for high X. 



satiu-ation region is theoretically inevitable. The theoretical expectations 

 are illustrated by the schematic figure 30.6. In the case of total absorption 

 of all wave lengths {i. e., conditions under which fig. 30.5 was obtained), 

 the curve for red light must bend earlier than that for green light (because 

 of the more uniform absorption of the latter throughout the cell layer). 



