Niels Formulation of Photosynthesis as an Oxidation-Reduction Process

Van Niel s Formulation of Photosynthesis as an Oxidation-Reduction Process (1931) 

For both cases, van Niel was able to express his postulated reaction in rather formal terms as the production of an oxidant S or OH and a reductant H. In other words, light produces a coordinated oxida- 

Accordingly, in the current view, the absorption of light is understood to produce a primary photochemical charge separation, between a chlorophyll-type, primary electron donor and a primary electron acceptor, resulting in the reactions going through a series of intermediate electron-transfer steps. 

One important consequence of van Niel s formulation is that in green-plant photosynthesis, the O2 evolved should originate from H2O, not CO2. This was soon confirmed experimentally by Ruben, Randall, Kamen and Hyde by mass-spectrometric examination of oxygen evolved by the alga Chlorella suspended in 0-labeled water. In retrospect, van NieTs simple and elegant postulate had provided one of the most important cornerstones for our understanding of the mechanism of photosynthesis during the past half century. For an in-depth discussion of the evolution of van NieTs concept, see the review by Clayton . 

---