Photosynthesis II

M. GIBBS and E. LATZKO In the preface to his Experiments upon Vegetables, INGEN-Housz wrote in 1779: "The discovery of Dr. PRIESTLEY that plants have a power of correcting bad air . . . shows . . . that the air, spoiled and rendered noxious to animals by their breath ing in it, serves to plants as a kind of nourishment. " INGEN-Housz then described his own experiments in which he established that plants absorb this "nourishment" more actively in brighter sunlight. By the turn of the eighteenth century, the "nourishment" was recognized to be CO . Photosynthetic CO2 assimilation, the 2 major subject of this encyclopedia volume, had been discovered. How plants assimilate the CO was a question several successive generations 2 of investigators were unable to answer; scientific endeavor is not a discipline in which it is easy to "put the cart before the horse". The horse, in this case, was the acquisition of radioactive isotopes of carbon, especially 14c. The cart which followed contained the Calvin cycle, formulated by CALVIN, BENSON and BASSHAM in the early 1950's after (a) their detection of glycerate-3-P as the first stable product of CO fixation, (b) their discovery, and that by HORECKER 2 and RACKER, of the COz-fixing enzyme RuBP carboxylase, and (c) the reports by GIBBS and by ARNON of an enzyme (NADP-linked GAP dehydrogenase) capable of using the reducing power made available from sunlight (via photo synthetic electron transport) to reduce the glycerate-3-P to the level of sugars.

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With contributions by numerous experts

Contenu
I. Introduction.- II. CO2 Assimilation.- II A. The Reductive Pentose Phosphate Cycle.- 1. The Reductive Pentose Phosphate Cycle and Its Regulation.- 2. The Isolation of Intact Leaf Cells, Protoplasts and Chloroplasts.- 3. Studies with the Reconstituted Chloroplast System.- 4. Autotrophic Carbon Dioxide Assimilation in Prokaryotic Microorganisms.- 5. Light-Enhanced Dark CO2 Fixation.- II B. The C4 and Crassulacean Acid Metabolism Pathways.- 6. The C4 Pathway and Its Regulation.- 7. C4 Metabolism in Isolated Cells and Protoplasts.- 8. The Flow of Carbon in Crassulacean Acid Metabolism (CAM).- 9. CAM: Rhythms of Enzyme Capacity and Activity as Adaptive Mechanisms.- 10. ?13C as an Indicator of Carboxylation Reactions.- II C. Factors Influencing CO2 Assimilation.- 11. Interactions Between Photosynthesis and Respiration in Higher Plants.- 12. The Interaction of Respiration and Photosynthesis in Microalgae.- 13. Effect of Light Quality on Carbon Metabolism.- 14. Photoassimilation of Organic Compounds.- 15. Biochemical Basis of Ecological Adaptation.- II D. Regulation and Properties of Enzymes of Photosynthetic Carbon Metabolism.- 16. Light-Dependent Changes of Stromal H+ and Mg2+ Concentrations Controlling CO2 Fixation.- 17. Ribulose-1,5-Bisphosphate Carboxylase.- 18. Carbonic Anhydrase.- 19. Enzymes of the Reductive Pentose Phosphate Cycle.- 20. Enzymes of C4 Metabolism.- 21. Enzymes of Crassulacean Acid Metabolism.- 22. Interaction Between Photochemistry and Activity of Enzymes.- II E. Metabolism of Primary Products of Photosynthesis.- 23. Metabolism of Starch in Leaves.- 24. The Enzymology of Sucrose Synthesis in Leaves.- II F. Glycolic Acid and Photorespiration.- 25. Glycolate Synthesis.- 26. Glycolate Metabolism by Higher Plants and Algae.- 27. Photorespiration: Studieswith Whole Tissues.- 28. Photorespiration: Comparison Between C3 and C4 Plants.- III. Ferredoxin-Linked Reactions.- 1. Transhydrogenase.- 2. Oxygen Activation and Superoxide Dismutase in Chloroplasts.- 3. Ferredoxin-Linked Carbon Dioxide Fixation in Photosynthetic Bacteria.- 4. Reduction of Nitrate and Nitrite.- 5. Photosynthetic Ammonia Assimilation.- 6. N2 Fixation and Photosynthesis in Microorganisms.- 7. Symbiotic N2 Fixation and Its Relationship to Photosynthetic Carbon Fixation in Higher Plants.- 8. Photosynthetic Assimilation of Sulfur Compounds.- 9. Hydrogen Metabolism.- Author Index.