Kinetics of Photosynthesis

Abstract

BALY and Morgan1 have proposed kinetic equations which account for observations of Warburg2 and Emerson3 on the rate of photosynthesis. We wish to direct attention to one of Warburg's observations which is not in accordance with their equations. At low light intensities, the temperature coefficient of photosynthesis approaches unity, while at low carbon dioxide concentrations it remains high. We have confirmed this for five different species of algae. This leads us to suppose that carbon dioxide is a reactant in the temperature-sensitive reaction, rather than in the photochemical reaction, where Baly and Morgan placed it. Their assumption seems to us untenable because it leads to equations in which light intensity and carbon dioxide concentration are interchangeable, and because according to photo chemical principles a photochemical primary process is unimolecular, taking place immediately on the absorption of light.