The Action Potentials Obtained from Venus's-Flytrap

Abstract

Following stimulation by bending a single trigger hair of Dionaea muscipula, action potentials were drawn off various leaf surfaces using non-polarizable Ag-AgCl electrodes. Records were made with a Dumont 208B cathode ray oscillograph with a Y-axis pre-amplifier; transients on the fluorescent screen were compressed to 2 in. and photographed with a Monitor camera using an F/4.5 lens. The action potentials ran a course comparable to that of mammalian nerve. The rising phase of the spike is smooth and reaches a peak in 0.1 sec. the falling phase of the spike is much slower; the spike is overlapped and followed by a negative after-potential which in turn is followed by a positive after-potential; and return to resting level is completed in 1.5 sec. Transients became broader and lower with increasing distance from the point of stimulation. The action potential ran its course without closure of the trap.