The electrical potentials of Chara vulgaris

An electric polarity corresponding to the morphological axis has been established in Obelia and other hydroids (3, 8), the Douglas fir (14), the onion root (10), the frog skin (12), the oat coleoptile (4, Wilks, loc. cit.) the bean plant (27) and other polar structures. These continuously maintained E.M.F.'s have been shown to be quantitatively linked with the oxidation mechanism of the living cell. The E.M.F. appears to depend upon the flux equilibrium in an electrochemical system made up of substances necessary for cell oxidation, and on the presence of atmospheric oxygen. The polarities of these living systems have been shown to be affected by changes in temperature, anaesthetics, oxygen, mechanical stimulation, light, externally applied E.M.F.'s and other factors affecting cell oxidation. A theory of cell correlation which explains the method by which a group of electrically dominant cells may control the rate and orientation of physicochemical processes in the adjacent cells has been advanced by Lund (11). In order to determine whether or not the general principles which have been discovered in the phenomena of electric polarity of complex animals and higher plants also were to be found in simpler polar cell aggregates, the green aquatic stonewort, Chara vulgaris, was selected for study. The purpose of this investigation was first to determine the normal distribution, magnitude, and degree of stability of the potential differences along the main axis; second, to demonstrate how mechanical stimulation can reversibly affect the electric polarity. The third problem was to study the nature of the effect of light energy on the electric polarity, and the possible relation of electric polarity to photosynthesis. Although some observations have been made on the electrophysiology of Chara (1, 7) and more on its close relative Nitella (22, 23, 24), no investigator has determined the distribution of maintained potential differences in the normal unstimulated plant