Abstract

The paper concerns influence of water distribution on the bioelectric potential in the soil–plant system. Two methods for measuring bioelectric potentials (BEPs) of plants have been compared, namely an invasive installation of needle electrodes (a) and a noninvasive method of providing contact due to root intergrowth through a metal grid (b). It has been shown that needle electrode installation into plant tissue leads to a decrease in the biopotential difference from 70 mV to a noise level within ~ 30 minutes; in fact, this means measuring the potentials generated by the plant organism due to the stress caused by the damage. On the contrary, noninvasive electrode installation provides long-term measurements for months and even longer. A specific system is suggested for automated electrophytogram based on the noninvasive method. It allows one long-term measurement of the plant electrophysiological signal directly under normal living conditions for the rhizosphere; it indicates the current functional state of a plant. An equivalent BEP measurement scheme has been proposed accounting for both electrical properties of the plant and root–inhabited medium. BEPs have been measured under conditions of varying water content in the root zone and water movement along and against the root growth direction. The biopotential is constant on average and fluctuates stochastically in the range from 245 to 275 mV at 60–70% of the total water capacity of the soil substrate. The bioelectric potential decreases almost twice when the soil dries. It is restored after irrigation and the restoration delay time increases with increasing water-deficit period. A model is proposed describing the effects in the system during a water-deficiency regime and irrigation.

中文翻译：

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灌溉过程中植物根区生物电势的动态变化

摘要

本文涉及水分配对土壤-植物系统中生物电势的影响。比较了两种测量植物生物电势（BEP）的方法，一种是侵入式安装针状电极（a），另一种是通过根系通过金属网格进行互生而提供接触的非侵入性方法（b）。已经证明，在植物组织中安装针电极会导致生物电势差从70 mV降低到30分钟内的噪音水平；实际上，这意味着要测量由于破坏所引起的压力而引起的植物生物体产生的电势。相反，无创电极安装可提供数月甚至更长的长期测量。建议基于无创方法的自动电植检仪的特定系统。它可以在根际正常生活条件下直接对植物的电生理信号进行一次长期测量；它指示工厂的当前功能状态。已经提出了一种等效的BEP测量方案，该方案考虑了植物和根系居住介质的电特性。已在根区含水量变化以及水沿着根生长方向和逆着根生长方向运动的条件下测量了BEP。在土壤基质总水容量的60％至70％范围内，生物势平均是恒定的，并且在245至275 mV范围内随机波动。当土壤干燥时，生物电势几乎降低了两倍。灌溉后恢复，恢复延迟时间随缺水期的增加而增加。