The action of potassium cyanide on the chlorophyll mechanism of Nereocystis

Abstract

In connection with studies on the nature of the action of cyanide on cell respiration, it seemed of interest to test the effect which cyanide might have upon the mechanism of photosynthesis.Strips 1× 10 cm. cut from the frond of the large, Pacific coast kelp Nereocystis were used, and oxygen production was taken as a measure of photosynthesis using Winkler's method for determination of oxygen.That potassium cyanide (.00008 mol in the experiment given) can produce an apparently complete but reversible inhibition of photosynthesis is shown by the following condensed statement of results from a typical experiment.Photodynamic sensitization occurs when strips are exposed to light in the presence of higher concentrations (in the experiment cited below .00016 mol.) of cyanide. Injury occurs in proportion to the concentration of cyanide, as shown by table 2, which gives the degree of recovery of the strips, and the mechanism of photosynthesis in terms of capacity to produce oxygen in pure sea water in light, aft...