An apparatus for studying rapid electrophysiological responses to light demonstrated on Arabidopsis leaves.
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 (Vm) 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 31 s after light-on. The Vm returned to near its original value after approximately 3 min. The early changes in Vm have been proposed to result from effects of photosynthetically 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.
Spalding
E P
EP
Department of Botany, University of Wisconsin, Madison 53706, USA.
D000255:Adenosine Triphosphate / Q000378:metabolism; D017360:Arabidopsis / Q000502:physiology / Q000528:radiation effects*; D004594:Electrophysiology / Q000295:instrumentation*; D008027:Light; D008564:Membrane Potentials / Q000528:radiation effects
D000255:Adenosine Triphosphate