Axial Susceptibility Gradients in Algae

Abstract

1. In 14 species of marine algae, including 10 species of Rhodophyceae, 2 of Phaeophyceae, 1 of Chlorophyceae, and 1 of Cyanophyceae, a more or less definite gradient in susceptibility to KCN exists in the vegetative axes, and in several species in other parts also; the susceptibility being greatest, at least during growth and development, in the apical region and decreasing basipetally. 2. Since extended experiment with the lower animals indicates that the degree of susceptibility to cyanides and to many other agents and conditions is in a general way, and within certain limits, a rough measure of metabolic activity or of certain fundamental metabolic processes, probably primarily the oxidations, these axial differences in susceptibility in the algae are regarded as indicating the existence of axial metabolic gradients. If this conclusion be correct, the axis in these simple plants is identical with the axis of the animal organism in this respect. 3. The relations of physiological dominance and subordina...