The Path of Carbon in Photosynthesis (1937–1954)

Abstract

Chapter 6 turns to the investigation of the mechanism of carbon reduction in photosynthesis, which, by then, was known to be the “dark” (that is, light-independent) reaction of the process. The turning point of this project came with the advent of radioisotopes, as it was found that they could be used to trace the metabolic processes of plants and animals. The path-breaking work done by Martin Kamen and Samuel Ruben is described, that is, their experimental design to use radioactive carbon in the study of photosynthesis and their discovery of carbon-14 in 1940. However, the main part of the chapter reconstructs the subsequent work (after World War II) of the research team headed by Melvin Calvin and Andrew A. Benson, which eventually succeeded in elucidating the complex reaction cycle of photosynthetic carbon reduction. This team—generously supported by the AEC—was one of the first non-physical, large and interdisciplinary research groups at the time. It is analysed how the labour was divided within this group and which strategies guided the course of actions. Widespread heuristic moves were, for example, the transfer of knowledge from respiration to photosynthesis, the assumption that all biochemical reactions also run in reverse and the recombination of structural formula on paper.