Wave phenomena have been observed in numerous experiments with whole plants. One of possible mechanisms
of the long-distance high-speed signaling in high plants is connected with concentration waves that can propagate
through the conducting systems of plants. One-dimensional axisymmetrical stationary flow of a viscous liquid
with osmotically active dissolved component through a long thin rigid cylindrical tube is considered as a model of
the conducting vessel of the plant. Constant concentrations of the component at the inlet and outlet of the vessel
are maintained by the live cells of the vegetative organs of the plant. Nonlinear concentration distribution along
the tube and the parabolic velocity profiles are obtained. Propagation of small excitations of concentrations and
velocities along the tube is considered. Expression for the wave velocity U is presented. The range U=20-60 m/s is
obtained by numerical estimations at wide variations of the parameters within the physiological limits. The time
delay in signal transmission in the system root-leaves corresponds to the experimental data. In that way the
concentration waves can mediate high-speed transferring of information between the organs of plants.
