同期検波による植物生体内水分測定法

抄録

It is important to measure water content for analyzing plant physiology and controlling plant growth. There are some reports about measurement of it. They are the capacitance method that detects change of capacitance between two electrodes on a stem in proportion to the change of amount of water in a stem.
It is tried to measure the capacitance between the two electrodes on a stem by the easy electric circuit using the phase sensitive detector with analog switches and IC operational amplifier. The output voltage of this electric circuit is in good proportion to the change of the known capacitance and shows the response of water content in the stem of the poinsettia with vibration to sudden switching on and off of light like step-function.