DANIEL I. ARNON 



553 



T154-6 



30' 



CE,(AP),G-l-P 





u 



z 

 < 



OtHYDRC»(YACET(]NE 

 PHOSPHATE 





PH0SPHCX3LYCERATE 



MONOPHOSPHATES 

 (GLUCOSE.FRUCTOSE) 



DIPHOSPHATES 

 (FRUCTOSE.RieULOSE) 



PHei«a./w*TER 



Fig. 25. Radioautograph of a chiomatogram showing products of dark C'^Oo 

 assimilation by a chlorophyll-free extract of chloroplasts. Experimental conditions 

 as in Treatment I of Table 15 (Trebst, Tsujimoto, and Arnon, 153). 



three conditions: (a) when the photochemical phase was limited to 

 non-cyclic photophosphorylation (reaction 5) , (b) when the photo- 

 chemical phase was limited to cyclic photophosphorylation (Fig. 5) , 

 and (c) when the photochemical phase included both (a) and (b) . 



Figs. 26 and 27 show that under conditions (a) and (b) CO2 as- 

 similation was liiTiited almost entirely to the formation of phospho- 

 glycerate. As shown in Fig. 28, the formation of sugar phosphates, 

 which is taken as a measure of a reductive (photosynthetic) COo as- 

 similation in this reconstituted chloroplast system, was observed only 

 in case (c) , when a proper balance was established between cyclic 

 and non-cyclic photophosphorylation. 



In the experiments illustrated by Figs. 26, 27, and 28, the balance 



