Simulation of Variation Potential in Higher Plant Cells

Abstract

Variation potential (VP), a propagating electrical signal unique to plants, induces a number of changes in many physiological processes. However, the mechanisms of its generation and propagation are still under discussion and require experimental and theoretical analysis, including VP simulations. The mathematical model for VP formation in plants has been worked out and is based on our previous description of electrophysiological processes in higher plant cells, including plasma membrane ion transport systems (K(+), Cl(-) and Ca(2+) channels, H(+) and Ca(2+)-ATPase, 2H(+)/Cl(-) symporter and H(+)/K(+) antiporter) and their regulation, ion concentration changes in cells and extracellular spaces and buffers in cytoplasm and apoplast. In addition, the VP model takes into account wound substance diffusion, which is described by a one-dimensional diffusion equation, and ligand-gated Ca(2+) channels, which are activated by this substance. The VP model simulates the experimental dependence of amplitude, velocity and shape of VP on the distance from the wounding site and describes the influence of metabolic inhibitors, divalent cation chelators and anion channel blockers on the generation of this electrical reaction, as shown in experiments. Thus, our model favorably simulates VP in plants and theoretically supports the role of wound substance diffusion and Ca(2+) influx in VP development.

Variation potential in higher plants: Mechanisms of generation and propagation

“…Redrawn from works. 11,46,56 In contrast, the homogenate didn't change VP, induced by cut, in pea. 54 The exact nature of the wound substance isn't known.…”

“…46,47,56 This decrement was about 10% cm ¡1 in pumpkin 46 and wheat. 47 Our theoretical investigation 56 showed that this decrement depends on initial damage intensity. Another interesting property of VP propagation is its transmission through inactive or dead plant parts.…”

“…It was shown that homogenates can induce an electrical reaction in mimosa, 11 biophytum, 62 and tomato. [63][64][65] 56 Electrical signals were registered in 7 cm from zone of stimulation. Redrawn from works.…”

“…Another possible way of wound substance propagation was suggested previously. 47,56 It is known that water flows in xylem are rather turbulent, 82 and diffusion in turbulent flow is 3-4 orders of magnitude faster than molecular diffusion, 79 and velocity of turbulent diffusion is similar to the speed of VP propagation. 47 Therefore, we proposed that wound substance propagation is based on turbulent diffusion.…”

“…1). 46,56 Propagation of VP has a number of specific properties. It is known that VP amplitude is proportional to the intensity of the damaging stimulus.…”