INFLUENCE OF VARIOUS FACTORS ON FLASH YIELD 



1463 



inhibition in continuous light, cf. chap. 33, sect. A6). In describing an- 

 aerobic induction we noted its twofold character: an extremely strong 

 effect, attributable to the production of an acid, diffusible, metabohc 

 poison, and a weaker effect, apparently due to enhanced production of the 

 (nondiffusible, nonneutralizable) "internal narcotic" — perhaps the same 

 that is also responsible for the induction losses in the aerobic state. Of 



UJ 



m 



3 



6 

 5 

 ;</) 4 - 



UJIO 



{5- 



O 2- 



o 



X 



1 - 



3.0r 



10 12 



DARK TIME, sec 



Fig. 34.18. Flash yield as function of 

 dark time for cells with low chlorophyll 

 concentrations (circles) and high chloro- 

 phyll concentration (dots). The ratio of 

 the two concentrations is about 4:1; the 

 saturation levels correspond to about 4 

 mm. 3 O2 and 1 mm.^ O2 per mm.^ cells, 

 respectively (after Emerson and Ai-nold 

 1932). 



2.5- 

 2.0 



1.5 



1.0 



0.5 



0.0034% urethone 



, IQ- 



2 4 6 8 10 12 



DARK TIME, sec. 



Fig. 34.19. Effect of phenylurethan 

 on course of dark reaction (after Emer- 

 son and Arnold 1932). 



these two aspects of anaerobic inliibition, only the second one appears to 

 affect the oxygen production by single flashes. When several such flashes 

 are produced in succession, the flash yield shows the typical short induction 

 phenomenon, with or without a second minimum (fig. 34.17). 



The absolute value of the maximum flash yield under anaerobic condi- 

 tions, although smaller than in air, is not so much smaller as to make the 

 application of the anaerobic method to the problem of [CO2] influence on 

 flash yield entirely unreasonable. 



The second point to be considered is the duration of the flash bulb ex- 

 plosions. As mentioned before, it is 0.04 second longer than the Emer- 

 son-Arnold period at 20° C. Therefore, the maximum yield obtain- 

 able per flash could be somewhat higher than the amount produced by a 

 single action of the available Eb (since the catalyst can act more than 



