Theoretical Analysis of the Influence of Fluctuations in the Activity of the Plasma Membrane H +-ATPase on Low-Temperature-Induced Electrical Responses in a Plant Cell

摘要

Fluctuations in physiological processes are a key property of biosystems; these fluctuations can play both positive and negative roles in living organisms. In particular, fluctuations in the activity of ion channels can increase sensitivity of the receptors and modulate the activity of neural networks. At the same time, a possible influence of fluctuations on the electrical activity in plants has not been investigated as yet. The aim of this work was a theoretical analysis of the influence of fluctuations in the plasma membrane H~(+)?ATPase activity on the low-temperature-induced electrical responses in a plant cell. The mathematical model of plant electrogenesis developed by the authors earlier, which was modified by description of fluctuations in the H~(+)-ATPase activity, was used in this study. Fluctuations in the H~(+)-ATPase activity were described by multiplying the H~(+)flux through the H~(+)-ATPase by an additional random value with a normal distribution (its specific values were recalculated every 1 s; the mean value was 1). The analysis of the model has shown that an increase in the magnitude of fluctuations in the H~(+)-ATPase activity was accompanied by (i) a non-linear increase of fluctuations in the membrane potential at rest; (ii) a decrease in the threshold of generation of simulated action potential when analyzing individual cells simulated by the model; and (iii)?modification of low-temperature-induced changes in the membrane potential when averaging electrical activity over a large sample of cells. The obtained results theoretically predict that fluctuations in the H~(+)-ATPase activity can decrease the threshold of generation of electrical responses in a plant cell upon cooling.