ISSN 1021-4437, Russian Journal of Plant Physiology, 2008, Vol. 55, No. 2, pp. 285–291. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © S.S. Pyatygin, V.A. Opritov, V.A. Vodeneev, 2008, published in Fiziologiya Rastenii, 2008, Vol. 55, No. 2, pp. 312–319.
The functional role of action potentials (AP) in
higher plant organisms attracts close attention of
researchers [1–5]. This role has been studied most thor-
oughly for a relatively small group of so-called
“motile” plants that employ AP in fast locomotory
responses analogous to seismonastic movements [2, 6].
The AP seems also involved in preparing plant genera-
tive organs to fertilization [7, 8].
The function of AP is less certain for vegetative
organs of higher plants, where AP are generated and
propagated along the stem over long distances under
the action of adverse factors . Presently, it is only
known that AP behave as fast distantly transmitted sig-
nals that induce short-term transient changes of many
vitally important processes (respiration, photosynthe-
sis, growth, etc.) along the route of their propagation [1,
The following questions remain opened so far:
(1) If AP is a signal, what kind of information it
(2) What is the mechanism for accomplishing the
AP signaling role?
(3) What is the meaning of AP-induced short-term
effector response? What does it signify?
This article is an attempt to provide comprehensive
responses to the above questions based on investiga-
tions performed in our laboratory.
WHAT KIND OF SIGNALING INFORMATION
IS CARRIED BY ACTION POTENTIAL?
The generation of AP in cells of vegetative organs of
higher plants is preceded by the appearance of a gradual
bioelectric response. This gradual response consists in
plasma membrane depolarization whose properties are
similar to those of the receptor potential [9, 10]. When
the depolarization attains a certain critical (threshold)
level, AP is generated according to the “all or none”
rule . The action potential appears usually as a sin-
gle pulse; in rare cases several repeated pulses are gen-
erated [11, 12]. Next, AP propagates along the conduct-
ing bundles of stem beyond the area of its generation [1,
13, 14]. After reaching leaves, roots, ovary, etc., the
propagating AP induces functional responses in these
organs. There is no unanimous view on whether AP
propagates over the root and the leaf directly or as a
transformed signal or whether it acts via a series of
The generation of AP in excitable higher plant cells
is chronologically linked to the early stage of stimulus
action . This circumstance clearly indicates the
alarming (signaling) function of the pulsed bioelectric
response. One may suppose that the purpose of this bio-
electric response is the transmission of some informa-
tion to resting tissues and organs. Meanwhile, analysis
shows that the AP transmitted beyond the region of
stimulation apparently cannot transfer information on
the quality of stimulating external factor; it can only
signalize about the onset of this factor action. Two rea-
sons support this inference.
(1) The transmission of frequency-coded informa-
tion, as it occurs in animals, would require repeated
pulsed activity, which is uncharacteristic of plants. Fur-
thermore, unlike animals, the plants have no special-
Signaling Role of Action Potential in Higher Plants
S. S. Pyatygin, V. A. Opritov, and V. A. Vodeneev
Department of Biophysics, Faculty of Biology, Nizhni Novgorod State University,
GSP-20, pr. Gagarina 23, Nizhni Novgorod, 603950 Russia;
Received February 13, 2007
—The signaling role of action potential (AP) in higher plants is considered. The principles underlying
realization of this role and the signiﬁcance of AP-induced short-term effector response are discussed. The
notion is put forward that the effect of propagating AP on plant cells is similar to nonspeciﬁc component of the
cell functional response to external stimuli.
Key words: higher plants - action potential - signaling role
: AP—action potential (potentials).