A leaf-mounted thermal sensor for the measurement of water content

作者：Atherton Joseph J^*; Rosamond Mark C; Zeze Dagou A

来源：Sensors and Actuators A: Physical , 2012, 187: 67-72.

DOI：10.1016/j.sna.2012.06.021

• Thermal sensor
• Leaf
• Water content

We present a microfabricated thermal sensor for the real-time measurement of the water content of plant leaves. The device consists of a thin-film micro-heater which induces a temperature gradient within a leaf to which it is attached. Temperature differences (Delta T) between two thin-film thermocouples spaced 50 mu m and 160 mu m from the heater can be related to the thermal properties of the sample under inspection which, in turn, are dependent on the leaf water content. The sensor is fabricated on a flexible polyimide substrate to ensure that it is robust enough to operate reliably without causing visible damage to the leaves. %26lt;br%26gt;To demonstrate the device%26apos;s operation, it was clamped to abscised leaves which were allowed to dry over a period of around 6 h. The device%26apos;s output was then compared to the relative water content of the leaf which was directly measured by weighing the leaf. For the range considered, a linear dependence was observed between Delta T and the water content of the leaf. It is suggested that the changes in Delta T are dominated by the thermal contact resistance between the device and the leaf. The device was subsequently used to monitor the real-time water content of leaves in situ on plants subjected to water stress conditions.

• 出版日期2012-11