CONTENTS XI 



Chapter S, contd. PaGE 



3. Carbon Dioxide Absorption by Amines 181 



4. Carboxylation Equilibria 183 



5. Is Carboxylation a Reduction of Carbon Dioxide? 187 



B. Carbon Dioxide Fixation by Living Cells 188 



1. Solubility of Carbon Dioxide in Plant Sap 189 



2. Conversion of Carbon Dioxide into Bicarbonate in Plants 189 



3. Role of Bicarbonate Ions in Photosynthesis 195 



4. Carboxylation and the jCOi} Complex 200 



5. Carbon Dioxide Fixation by Heterotrophants 208 



Bibliography 209 



Chap. 9. The Nonphotochemical Reactions in Photosynthesis. II. Reduction of 



Carbon Dioxide 213 



1. The Standard Bond Energies 213 



2. Reduction Level and Energies of Combustion, Dismutation, and 

 Hydration 214 



3. Energies of Hydrogenation and Oxidation-Reduction Potentials 217 



4. Formation of Carboxyl Groups in Respiration. The Role of 

 Phosphorylation 222 



5. Phosphorylation and Photosynthesis 226 



6. The Thermodynamics of Free Radicals 229 



7. Free Radicals in Photosynthesis and Chemosynthesis 233 



8. Metal Complexes as Reduction Intermediates 239 



9. Transformations of the First Reduction Product of Carbon Di- 

 oxide 240 



10. Experimental Evidence Regarding the Mechanism of Reduction 



of Carbon Dioxide 241 



Bibhography 244 



Chap. 10. Intermediates in the Reduction of Carbon Dioxide 246 



A. The Problem of Intermediates in Photosynthesis; The Hypotheses 



of Liebig and Baeyer 246 



B. Low Molecular Weight Compounds in Green Plants 248 



1 . Review of Analytical Data 248 



2. The Volatile Components of Green Leaves 252 



C. The Formaldehyde Problem 255 



1 . The Search for Formaldehyde in Leaves 255 



2. Formaldehyde Feeding Experiments 257 



3. Feeding of Plants with other Low Molecular Weight Compounds 260 



D. The Problem of Plant Acids 262 



1. Occurrence of Plant Acids in Leaves 262 



2. Acidification of Succulents 264 



3. Plant Acids in Xonsucculents 267 



E. Ascorbic Acid in Green Plants 269 



1. Ascorbic Acid in the Chloroplasts 269 



2. Ascorbic Acid — An Intermediate or Catalyst? 271 



Bibliography 273 



Chap. 11. The Nonphotochemical Reactions in Photosynthesis. III. Liberation 



of Oxygen 281 



1. The Peroxide Problem 281 



2. The Hydrogen Peroxide Hypothesis 282 



