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J. A. BASSHAM AND K. SHIBATA 



partially filled even in these rather short light periods. The second 

 reservoir begins to he filled almost from the beginning, as can be seen 

 from the fact that the straight part of the curve can be extrapolated to 

 pass through the origin. The ratio of AP<, (absolute value) to total 

 chlorophyll content of the sample of algae is listed in Table I. The 



20 



15 



Ap; 



10 



4 5 



tg (rel ) 



Fig. 3. Ox\'gen generation per flash with change of Hght period. 



ratio extrapolated to zero light period is 0.204%, the reciprocal— 

 about 481 — is the number of molecules of chlorophyll for each mole- 

 cule of oxygen evolved. This number is much smaller than the previ- 

 ously reported photosynthetic unit of 2500. It may be that the value of 

 2500 resulted from weak light intensities employed in earlier experi- 

 ments. 



Another fact we might point out is that the first reservoir is almost 

 filled at about H msec. This time is calculated from the intersection 

 of the horizontal straight line and the extrapolated straight part of 

 the curve in Fig. 3. This time corresponds to the first fast decay 

 period of chemiluminescence, which was observed by Strehler et at. (5). 



