EN
Multichannel extracellular measurements of electrical potential changes allowed comparison of the electrical activity in two types of tomato: wild type (MTwt) and ABA-deficient, draught-sensitive mutant (MTsit). After electrical stimulation of the stem, MTsit generated action potentials (APs) with an amplitude of 40 mV and half-time (τ1/2) 19 s compared to MTwt 20 mV and 19 s, respectively. Intracellular microelectrodes were used to detect APs triggered by light in the leaves and cotyledons of MTwt. APs were characterized by long latency and their amplitudes were 77±2 mV and τ1/2 58±2 s in leaves, and 67±14 mV, τ1/2 13±2 s in the cotyledons. Turning off the light evoked 25 mV hyperpolarization in the leaf and 10 mV in the cotyledon.