Abstract
In this paper, electronic measurements of water content in plants with high sensitive impedance meter were discussed and dynamic characteristics of stemwater in tobacco plants by step input of environmental elements were made clear.
1) By step input of light (0lux to 30, 000 lux and 30, 000lux to 0lux) at the air temperature of 25°C and the air humidity of 60% RH, the variations of capacitance in the stem were about 1 pF and the time constant was about 30 min.
2) By step input of relative humidity (60% RH to 80% RH and 80% RH to 60% RH) at the air temperature of 25°C and light intensity of 30, 000 lux, the variations of capacitance in the stem were about 1pF and the time constant was 1 min to 10 min.
3) By step input of temperature (25°C to 30°C and 30°C to 25°C) at the air humidity of 60% RH and light intensity of 30, OOOlux, the variations of capacitance in the stem were about 0.5pF and the time constant was about 10 min.
4) By step inputs of light and relative humidity, the variations of capacitance in the stem were about 3 pF at maximum. Effects of complex inputs on dynamic characteristics of capacitance of the stem were examined.
5) Reliability of these values was examined on digital simulation.
