CHLOROPHYLL CONCENTRATION IN SINGLE CELLS 411 



Table 15.11 — Continued 



"W. S. = Willstatter and StoU; L. = Lubimenko; W. N. = Warburg and Negelein; S. E. = SeybolS 

 and Egle; N. E. = Noddack and Eichhoff; E. A. = Emerson and Arnold; Sa = Sargent; H. = Haskin. 

 ' Relative to fresh weight. 



considerably higher chlorophyll content in Porphyra laciniata than was 

 given by Lubimenko for any of the red algae. It remains to be seen 

 whether the decrease in chlorophyll concentration with increasing depth, 

 asserted by Lubimenko, will be confirmed by new analyses. 



7. Chlorophyll Concentration in Single Cells and Chloroplasts 



The highest chlorophyll concentrations (up to 1.7% of fresh weight 

 and 5% of dry weight) have been found in the unicellular green alga, 

 Chlorella, particularly in cultures grown in weak light. This must be 

 due to the absence of "dilution" by colorless cells and structures, which 

 is inevitable in multicellular organisms. (The concentration of chloro- 

 phyll in single palisade cells of green leaves may be as high as in Chlorella.) 



The concentration of chlorophyll within the chloroplasts must be two 

 or three times higher than in the cell as a whole. In the case of Chlorella, 

 it should reach 10-15% of the dry weight. Several empirical estimates 

 of this quantity have been attempted. Von Euler, Bergman, and 

 Hellstrom (1934) calculated that 1.7 X 10^ molecules of chlorophyll are 

 present in a single chloroplast of Elodea densa; this corresponds to a 

 concentration of about 0.1 mole per liter, or about 10% relative to the 

 fresh weight of the chloroplast. 



Godnev and Kalishevich (1940) found that a leaf of Mnium contained 

 an average of 2.4 X 10"^^ g_ or 1.3 X 10^ molecules of chlorophyll in 

 each chloroplast. Since the volume of an average chloroplast of Mnium 

 is 4.1 X 10~" ml., the concentration of chlorophyll in it is 0.065 mole 

 per liter, or about 5.8% of the fresh weight of the chloroplasts. 



Other estimates have been derived from the analysis of the "chloro- 

 plastic matter" isolated by methods described in chapter 14. Granick 

 (1938) found as much as 16% chlorophyll (relative to dry weight) in the 

 chloroplastic matter from spinach. The results of other analyses were 

 somewhat smaller. Menke (1940) found between 7.6 and 8.3% chloro- 

 phyll in the centrifuged chloroplast fraction from spinach leaves, and 5.3. 



