Electrophysiology and Phototropism

Abstract

Plants continually gather information about their environment. The conduction of bioelectrochemical excitation is a fundamental property of living organisms. Cells, tissues, and organs transmit electrochemical signals over short and long distances. The sensitive membranes in phloem cells facilitate the passage of electrical excitations in the form of action potentials. We have created a unique electrophysiological workstation that can effectively register this electrical activity in real time. It allows basic properties of electrical communication in green plants to be established. Our workstation has very high input impedance and a resolution of 0.01 ms. Excitation waves in higher plants are possible mechanisms for intercellular and intracellular communication in the presence of environmental changes. Ionic channels, as natural nanodevices, control the plasma membrane potential and the movement of ions across membranes regulating various biological functions. Some voltage-gated ion channels work as plasma membrane nanopotentiostats. Blockers of ionic channels, such as tetraethylammonium chloride and ZnCl₂, stop the propagation of action potentials in soybean induced by blue light and inhibit phototropism in soybean plants. Voltage-gated ionic channels control the plasma membrane potential and the movement of ions across membranes regulating various biological functions. These biological nanodevices play vital roles in signal transduction in higher plants. Tetraethylammonium chloride and ZnCl₂ block K⁺ and Ca²⁺ ionic channels. These blockers inhibit the propagation of action potentials induced by blue light, and inhibit phototropism in soybean plants. The irradiation of soybean plants at 450 ± 50 nm induces action potentials with duration times of about 1 ms and amplitudes around 60 mV. The role of the electrified interface of the plasma membrane in signal transduction is discussed.