Relation of potential differences to bud inhibition in Phaseolus multiflorus

Date

1935

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A theory of cell correlation has been formulated by Lund in which it is suggested that the continuous electrical currents produced by polar cells may control and modify the magnitude and direction of various processes in other cells. Lund and his co-workers have accumulated considerable evidence showing definite correlations between maintained electrical potentials and cell processes. One of the most interesting and familiar examples of cell correlation is the inhibition of the normally dormant axillary buds and the subsequent release of this inhibition after the decapitation of the plant. ... In 1933 Theiman and Skoog (8) demonstrated that the growth substance applied to the cut surface of the decapitated plant reversibly inhibited the buds. Although the concentration of the growth substance necessary to cause complete inhibition was many times greater than the amount normally existing in the apex, it seems probable that the growth substance is in some manner definitely linked with this inhibition. The question arose as to what role, if any, bioelectric currents play in this inhibition and regeneration. Are there in plants possessing inhibited axillary buds maintained electrical polarities capable of explaining bud inhibition? In the experiments reported here potted plants of the scarlet runner bean, Phaseolus multiflorus, were used. The work reported in the literature on electrical polarities in Phaseolus or closely related plants is meager. Muller-Hettlingen in the last century reported that the cotyledons of Vicia faba were positive in the external circuit to the other parts of the plant. But in view of more recent work this finding needs to be re-examined. No one, as far as the writer is aware, has studied the behavior of electrical polarities in relation to the phenomena of inhibition. Since the buds are inhibited continuously, one would expect, if bioelectric currents play a role in this inhibition, to find in this plant electrical polarities of relatively constant orientation. The first part of the experimental work was therefore devoted to a study of the distribution of electrical polarities in the plant for the purpose of discovering whether or not there were polarities that possessed a relatively constant orientation under various conditions. If such electrical polarities exist within the plant, they would be expected to undergo a definite change in decapitated plants during the regeneration of the buds. The second part of the experimental work comprises a study of the relation of these electrical polarities to bud regeneration. The experiments reported in Section V were performed in order to answer the following questions: (1) Do the measured P.D.'s originate within the plant, or are they artifacts due to the method of measurement? (2) Do the P.D.'s depend upon the activities of the living cells? (3) Are the P.D.'s capable of delivering continuous currents? (4) Is the P. D. measured between two loci contributed to by P.D.'s originating in the intermediate regions? The effect of applied currents on the node potentials is given in Section VI. The purpose of these experiments was to gain further knowledge of the electrical mechanism in this plant and also to render more intelligible future experiments on the effect of applied current on bud inhibition and regeneration

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