Spalding E P
Department of Botany, University of Wisconsin, Madison 53706, USA.
Photochem Photobiol. 1995 Nov;62(5):934-9. doi: 10.1111/j.1751-1097.1995.tb09159.x.
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.
构建了一种用于对植物细胞中光诱导的电生理变化进行高分辨率测量的装置。其主要组件包括一个氙弧灯、一个电子快门、一个液体光导、一台配备模数转换器的计算机以及一个控制快门和数据采集的计算机程序。该装置用于检测拟南芥叶片光照时发生的膜电位（Vm）瞬态变化。光照开启后经过0.53秒的延迟时间，诱导出4毫伏的瞬态超极化。随后是一个大得多的瞬态去极化，在光照开启后31秒达到峰值。大约3分钟后，Vm恢复到接近其原始值。有人提出，Vm的早期变化是由光合作用产生的ATP对质膜上H(+) - ATP酶和K+通道活性的影响导致的。发现初始超极化的动力学与这种机制相当一致。预计这里描述的装置将有助于未来对这种以及其他光诱导电生理反应的研究。
