Analysis of the Variation Potential Induced by Wounding in Plants

Following burning of a leaf portion, a bioelectrical wave called"variation potential" spread throughout the whole plant. Bioelectricalvariations are recorded by two types of electrodes (platinumwires and Ag/AgCl nonpolarizable electrodes) in the stem ofVicia faba and in the petiole of Lycopersicon esculentum andMimosa pudica. The time course of the variation potential thusrecorded can be divided into two components respectively calledcomponents "A" and "B". Component A looks like a negative spikybioelectrical change lasting about 1 min with an amplitude of20–50 mV spreading in front of the component B depictedby a more smooth and long-lasting (several min) wave of negativity.An attenuation of the signals recorded under the Ag/AgCl electrodesis noted compared to that recorded under the platinum wires.Moreover, component B is more attenuated than the componentA. Attenuation of the component A is nearly the same as thatnoted for the action potential in Mimosa pudica. All the parameters depicting the variation potential increaseapproximately in direct proportion to the amount of the damagedarea up to 400 mm² in Vicia faba; above this value, a maximalresponse is reached. (Received October 18, 1984; Accepted January 14, 1985)