OBSERVATIONS ON THE FORMATION OF THE PHOTOSYNTHETIC APPARATUS 297 



practically zero at 7-8" o oxygen in the gassing mixture (Fig. 2). A com- 

 bination of the curves in Figs, i and 2 results in the curve of Fig. 3 which 

 shows that chlorophyll concentration per volume of culture reaches a 



10- 



Va 



u 



2 



v/- 



20 



% Oxygen 



Fig. 2. Effect of oxygen tension in the gassing mixtures on the chlorophyll 

 content (in jug bacteriochlorophyll per ^\. of packed cells) of dark-grown cells 

 measured four days after inoculation. Original inoculum contained 0-024 P-S- 

 bacteriochlorophyll per jul. of packed cells. Culture conditions identical with those 

 indicated for Fig. i. 



Fig. 3. Effect of oxygen tension in the gassing mixtures on the chlorophyll 

 content per litre of bacterial culture suspension incubated in the dark, measured 

 four days after inoculation. This graph represents a combination of Figures i and 2. 



