Effect of Peroxyacetyl Nitrate on C14O2 Fixation by Spinach Chloroplasts & Pinto Bean Plants

Abstract

Photosynthetic CO2 fixation in pinto bean plants and in intact spinach chloroplasts was inhibited by peroxyacetyl nitrate, a component of photochemical smog. Addition of ascorbate to the chloroplast containing reaction mixtures virtually eliminated this inhibition. Exposing the chloroplasts or other components of the reaction, either separately or as a mixture, to peroxyacetyl nitrate in the dark followed by a light period without the oxidant did not effect the C14O2 fixation process. This inhibition in the intact plant, as well as in the chloroplast, appears to be 1 of quantitative reduction in the early products of the photosynthesis and not a qualitative change.