Research on the Measurement Method of Plant Sap Flow Rate Based on Electromagnetic Induction Law

Based on Low of Electromagnetic Induction, a uniform alternating magnetic field is provided to plant stem through excitation module. Sap flow cuts the magnetic flux lines, inducing electromotive force signal on sensor. The signal is processed by signal processing circuit, filtered, and amplified. After analog-to-digital conversion, the data is collected by microprocessor and transmitted to host computer for processing and storage. In the experiment, Radermachera Sinica was selected as the subject. The transpiration diurnal variation trends were analyzed through correlation analysis (r=0.894) between the results from the whole-plant weighing method and measurement method. The results showed a significant correlation between the two measurement methods. A linear fitting of the measurement method using the weighing method was performed (Slope: 0.0727, Intercept: 0.6611, R2=0,682) and data validation (1:1) was carried out, confirming the feasibility of the measurement method. This provides a new approach and method for studying plant transpiration.