An experimental apparatus for measuring electrical potential of crops

在试验的基础上设计了一种测量植物表面电位的实验装置，用于估计田间条件下作物的水分和营养胁迫(Exp。1)。并用四季豆(Exp.2)、马铃薯(Exp.3)和大米(Exp.4).Exp.l.所研制的电厂启动电压测量系统包括前置放大器、电源、为多个放大器供电的接线盒和校准器。用电压跟随式设计的高阻抗放大器测量了被控对象的激活电压。首先，确定了插入土壤中的铜管作为标准电极是可靠的。其次，通过测量茎中不同部位木质部的电势来检测表面电势的一个分量。为了考察表面电位日变化的不确定重复性，最后一次实验是通过测量黑暗房间中的表面电位来进行的。地面电压一般在日出后开始下降，中午维持低值，夜间升高。夜间和中午的差异约为50-100 mV，但同一植物的茎节间也存在差异，不同植物的茎节间也存在差异。水稻叶鞘不同部位的表面势不同，但它们是相加的。然而，表面电势的梯度与垂直位置不是线性的。电位的连续变化往往在某一位置被中断，并且中断的位置在一天中不时地移动。因此，测量位置上的微小差异(可能小于几毫米)将是单个植物之间潜在差异的主要原因。

An experimental apparatus on a trial basis designed for measuring electrical potential on a plant surface was made to estimate water and nutrient stress of crops under field conditions (Exp. 1). and tested with kidney bean (Exp. 2), potato (Exp. 3) and rice (Exp. 4).Exp.l. The developed system for measurements of activation voltage generating in the plants has pre-amplifiers, power source, connecting box to supply the power to many amplifiers, and calibrator. Activation voltage of the plants was measured with the high impedance amplifier designed by voltage follower type.Exp.2. In the first, copper tube inserted into soil was confirmed to be reliable as a standard electrode. Secondly, an electrical component of the surface potential was examined by measurement of electrical potential at xylem of different parts in the stem. To investigate uncertain repeatability on a daily change of the surface potential, last experiment was conducted by measurement of the surface potential in the dark room.Exp.3. The surface voltage generally started to decrease after sunrise, maintained low value during mid-day, and increased during the night. The difference between night and mid-day was about 50-100 mV.However, the difference was also found between the stem nodes of one plant and also of different plants.Exp.4. The surface potentials differed among positions in rice leaf-sheath, but they were additive. The gradient of the surface potential was not, however, linear with the vertical positions. Continuous change of the potentials was often interrupted at a certain position and the interrupted positions moved time to time throughout a day. Therefore, a small difference (possibly less than a few mm) in measurement positions will be a major cause of the potential variation among individual plants.