1021-4437/05/5206- © 2005
Russian Journal of Plant Physiology, Vol. 52, No. 6, 2005, pp. 801–808. Translated from Fiziologiya Rastenii, Vol. 52, No. 6, 2005, pp. 905–912.
Original Russian Text Copyright © 2005 by Opritov, Lobov, Pyatygin, Mysyagin.
The mechanisms of perception of environmental
signals by the plant cell attract increasing attention of
researchers. This interest is justiﬁed because signal
reception initiates a series of processes that constitute
the cell response. Signiﬁcant advances were achieved
in studying the reception of endogenous factors, e.g.,
phytohormones [1–3]. At the same time, the question of
how plants perceive exogenous signals (thermal,
mechanical, etc.) remains poorly investigated.
The perception of external stimuli in higher animals
is known to involve specialized cellular receptor sys-
tems (chemoreceptors, mechanoreceptors, etc.) .
The majority of vascular plants, except for plants with
locomotive functions [5–7], have no specialized recep-
tor structures. One may assume that the perception of
external stimuli (thermal, mechanical, chemical, etc.)
in plants is realized by virtue of cellular membranes,
the plasma membranes of epidermal cells in particular.
The molecular mechanisms of such perception are not
clear yet, but there are grounds to believe that changes
in the lipid matrix and in the state of membrane-incor-
porated channels, enzymes, and other protein structures
are implicated [7–9]. A certain specialization of mem-
brane elements sensing different signals seems possi-
ble. Some plant regions are particularly sensitive to
impact of speciﬁc external factors, which provides indi-
rect evidence for the above assumption .
The transformation of external stimulus energy into
the effector’s response proceeds through a series of
stages . Generation of local electric response, called
the receptor potential (RP) is apparently the most char-
acteristic and universal step at early stages of reception.
The RP of animals have some distinguished features
. First, their amplitude increases gradually with the
strength of external stimulus. Second, when the excita-
tion threshold is achieved, the RP generates the propa-
gating action potential (AP) that transmits information
on the environmental cue to other tissues and organs.
Thus, RP initiates the electrophysiological component
of receptor–effector relations. Third, the excitation
threshold depends on the steepness of stimulus; i.e., it
exhibits the accommodation phenomenon. Fourth, the
receptor cells are capable of sensory adaptation: their
RP arising in response to repeated stimuli differ from
the response to the ﬁrst stimulus. All these features of
RP are related to properties of membrane generator ele-
ments that are more or less speciﬁc to certain stimuli.
Local bioelectric responses (LBER) were frequently
recorded under the action of various environmental sig-
nals, including chilling [11–14]. However, it remains
unexplored whether these LBER correspond to the RP
criteria. The exceptions are characean algae, capable of
generating gradual electric responses upon mechanical
stimulation and AP in response to suprathreshold stim-
uli , as well as vascular plants with locomotive
Analysis of Possible Involvement of Local Bioelectric Responses
in Chilling Perception by Higher Plants
V. A. Opritov, S. A. Lobov, S. S. Pyatygin, and S. A. Mysyagin
Department of Biophysics, Faculty of Biology, Nizhni Novgorod State University,
GSP-20, pr. Gagarina 23, Nizhni Novgorod, 603950 Russia;
Received February 15, 2005
—Macroelectrodes and electrophysiological setup were used in experiments with stems of 15-day-old
L.) seedlings for computer-assisted data recording. It is shown that local bioelectric
responses induced by graded local chilling are similar to the receptor potentials of animals. These responses
increase gradually with stimulus strength and trigger the action potential generation when a temperature thresh-
old is attained. The excitation threshold of cells in seedling stems displays the phenomenon of accommodation.
Parameters of local bioelectric responses induced by intermittent cooling can undergo changes similar to sen-
sitization–habituation patterns. The results indicate that local electrical responses may be involved in early
stages of cooling perception in cells of higher plants devoid of locomotive functions.
Key words: Cucurbita pepo - local bioelectric response - action potential - receptor potential - accommodation -
: AP—action potential; LBER—local bioelectric
response; RP—receptor potential;
—temperature shift sufﬁcient
for local generation of action potential.