Plants generate different types of electrical events in connection to environmental stress. Cells, tissues, and organs transmit electrochemical signals over short and long distances. Action potentials in higher plants may be the information carriers in intercellular and intracellular communication in response to environmental changes. Here, we show the generation of bioelectrochemical responses induced by blue photosensory system in soybean plants. A phototropic response is a sequence of the four following processes: reception of the directional light signal, signal transduction, transformation of the signal to a physiological response, and the production of directional growth response. The irradiation of soybean plants at 450 ± 50 nm induces action potentials with duration times of about 0.3 ms and amplitudes about 60 mV. Action potentials play an active role in the expedient character of the response reactions of plants as a reply to external stimuli. Blockers of ionic channels inhibit phototropism in soybean plants. The role of the electrified interface of the plasma membrane in signal transduction is discussed.

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