Variation and action potentials evoked by thermal stimuli accompany enhancement of ethylene emission in distant non-stimulated leaves ofVicia faba minorseedlings

Electrical activity (action and variation potentials) and ethylene emission were measured in thermally stimulated Vicia faba minor seedlings. It was determined that variation potential with or without superimposed action potentials was generated and propagated basipetally in response to scorching of the upper leaf. In stimulated plants the level of ethylene production measured in lower, non stimulated leaf was significantly higher than that in the control plants and the difference correlated with the amplitude of the electrical response. Neither variation nor action potential was recorded when ethylene was injected to the chamber covering the experimental leaf. The level of ethylene emission showed clear circadian rhythm when measured at photoperiod 16 : 8 (LD) or at constant light (LL). It is concluded that the sequence of ion fluxes registered as an electrical response of a plant to the thermal stimulus is a signal evoking an enhancement of ethylene emission.