CHROMATIC TRANSIENTS AND ENHANCEMENT RECORDED 

 BY THE GLASS ELECTRODE 



L. R. Blinks 



Blinks and Skow ^-^^ showed that a glass electrode surface in 

 direct contact with tissues or cell suspensions could be used 

 to indicate the exchange of CO2 (or other acids) dirring respira- 

 tion and photosynthesis. Transients were recorded^ with "acid 

 gushes" sometimes occurring during the first moments of illumina- 

 tion, preceding the expected rise of pH. These were later 

 detected manometrically by Emerson and Lewis V^j a.nd identified 

 as CO2 gushes. They have since been designated the "First 

 Emerson Effect." The cause of this acid gush is still unknown, 

 and deserves further study. 



Later , applications of the glass electrode were made by 

 Gaffron ^-'^ Rosenberg '^/, and most recently by Blinks and van 

 Niel (5), who followed the consumption of acetate in Rhodo - 

 spirillum rubr\mi by its means. They found no evidence of photo- 

 synthetic enhancement in these bacteria, when the latter were 

 simultaneously illuminated at two or more critical absorptive 

 regions of the constituent pigments. There was only a simple 

 addition of rates. While this was in accord with expectation, 

 since there is no oxygen evolving mechanism in R. rub rum , it 

 nevertheless seemed desirable to employ the same method with 

 algae, where both manometric and polarographic oxygen evolution 

 measurements had shown good enhancement v^WjoJ. 



In the present paper both enhancement and chromatic tran- 

 sients are shown in the photosynthetic fixation of CO2 by 

 several algae, when illuminated simultaneously or consecutive- 

 ly with essentially monochromatic light absorbed by chlorophyll 

 a and one or another of the "accessory pigments" such as chloro- 

 phyll b, phycobilins or carotenoids. 



Two arrangements were employed: one, best adapted to suspens- 

 ions of cells or filaments in fluids, gives a progressive, cumu- 

 lative record of the CO2 exchange; the other, best adapted to 

 thin tissues or membranes yields steady state, direct rate 



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