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AN APPARATUS FOR STUDYING RAPID ELECTROPHYSIOLOGICAL RESPONSES TO LIGHT DEMONSTRATED ON Arabidopsis LEAVES
Author(s) -
Spalding Edgar P.
Publication year - 1995
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1995.tb09159.x
Subject(s) - hyperpolarization (physics) , electrophysiology , depolarization , membrane potential , shutter , biophysics , chemistry , optics , physics , neuroscience , biology , organic chemistry , nuclear magnetic resonance spectroscopy
— An apparatus for making high‐resolution measurements of electrophysiological changes induced by light in plant cells was constructed. Its main components were a xenon arc lamp, an electronic shutter, a liquid light‐guide, a computer equipped with an analog‐to‐digital converter and a computer program that controlled the shutter and data acquisition. The apparatus was used to examine transient changes in membrane potential (V m ) that occur upon illumination in Arabidopsis leaves. Light‐on induced a transient hyperpolarization of 4 mV after a lag time of 0.53 s. It was followed by a much larger transient depolarization that peaked 31s after light‐on. The V m returned to near its original value after approximately 3 min. The early changes in V m have been proposed to result from effects of photosyn‐thetically produced ATP on the activities of H+ ATPases and K+ channels at the plasma membrane. The kinetics of the initial hyperpolarization were found to be reasonably consistent with such a mechanism. It is expected that the apparatus described here will be useful in future investigations of this and other electrophysiological responses to light.