Transients in the Carbon Dioxide Gas Exchange of 



Algae 



HANS GAFFRON, Department of Biochemistry (Pels Fund), University of 



Chicago, Chicago, Illinois 



At the first Gatlinburg meeting three years ago, I showed some 

 induction curves for carbon dioxide obtained with a Beckman com- 

 mercial pH meter, a glass electrode, and a Brown recorder. A glass 

 electrode registering acidity changes caused by carbon dioxide was 

 used years ago by Blinks and Skow (1). Rosenberg in the meantime 

 has published a paper describing within what limits our method per- 

 mits the quantitative measurement of the carbon dioxide exchange 

 in thin suspensions of algae (2). Our original purpose was to supple- 

 ment the manometric method with a fast and automatically re- 

 cording one, to see whether the strange phenomenon reported by 

 Warburg and Burk, known as "the one quantum process," really 

 existed. We found no trace of it, in best agreement not only with our 

 own experiences throughout many years but also with the results 

 of Brackett and Olson, Brown, Whittingham, Calvin and, of course, 

 Emerson. Our efforts in this respect have been published (together 

 with a list of references) and there the matter may rest (3) . 



Fortunately it turned out that this very sensitive, reliable, and 

 fast method revealed a number of new aspects of the induction period 

 and other transients for carbon dioxide which have not been discussed 

 before. 



I shall show a few selected curves, particularly those which invite 

 direct comparison with Brackett and Olson's transients for oxygen 

 ((4) and pages 412-418, this book) and with McAllister and Myers' 

 old induction curves for carbon dioxide (5). 



To forestall some obvious questions we contrast (Fig. 1) acidity 

 changes during transients as found in phosphate buffer lacking carbon 

 dioxide with those seen in bicarbonate buffer. At pH 6.9 in phosphate 

 buffer with little free CO2, the algae seem not to notice much whether 

 the hght is being turned on or off. If organic acids other than carbonic 

 are being suddenly released into, or suddenly reabsorbed from, the 



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