抄録
A probe was improved for measuring the rate of water flow in the stem of intact plants with the stem heat balance method. It consists essentially of flexible flat heater for feeding constant heat energy to a plant stem, heat flow sensing element for determining heat loss from the surface of the heater to the surrounding air and thermocouples for detecting stem temperatures. The improved probe can be easily set and removed to/from the stem and hardly arrests the radial growth of the plant stem. The comparison of the transpiration rate measured by a balance and the water flow rate determined by the new probe showed that the new probe was able to determine the water flux in a thin plant stem with acceptable error which was almost the same level attained with the original measuring device.
