1328 



INDUCTION PHENOMENA 



CHAP. 33 



found to be, as a rule, unchanged by illumination, while sudden, but rela- 

 tively small, increases in respiration were occasionally noted after the end 

 of an illumination period). 



A similarly bewildering variety of carbon dioxide induction phenomena 

 will be described in the next section — ranging from a photochemical carbon 

 dioxide gulp (van der Xeen, Warburg) to a photochemical carbon dioxide 

 burst (BUnks, Emerson, van der Veen). 



+6 

 +4 

 ■t-2 

 

 -2 

 -4 



g +2 

 = -2 



.70 



^/ .60 

 .50 



40 



imr 



;+8 



t4 



t2 







-2 



»-4 



I 



+4 



+2 



O 



-2 



E 



T 1 1 r 



16 18 2 4 6 8 10 12 14 16 18 

 TIME IN MINUTES 



"T — I 1 — r 



n 



T — r — r 



16 18 2 4 6 8 10 12 14 16 18 

 TIME IN MINUTES 



Fig. 33. 6C. Two-vessel manometric measurements (after Emerson and Chalmers 

 1954). O2 liberation by Chlorella in carbonate buffer, in vessel pairs of type H, hi 

 (left) and H, hi (right) (cf. fig. 29.4A). Minute-by-minute pressure changes measured 

 by twin differential manometers. The ratio of measured pressure changes varies in the 

 two vessels on left, remains nearly constant on right, indicating synchronous reaction. 



All these results leave one with the impression that rapid fluctuations 

 of gas exchange after the transfer of cells from darkness to Ught (or light 

 to darkness) are "transients," caused by readjustments of the catalytic 

 systems (and intermediate products) to new steady states (in other words, 

 typical induction effects), rather than "tail ends" of steady activities in 

 the preceding periods. 



This impression is further strengthened by new observations of Emer- 

 son and Chalmers (1954), who were able to improve considerably the 

 precision of the two-vessel manometric method by using a dou))le differen- 

 tial manometer, making simultaneous readings with two cathetometers. 

 Two matched light beams from the same source were thrown onto two 



