METHOD FOR DETERMINING A RELATIVE CHANGE IN A SAP FLOW DENSITY IN A VASCULAR PLANT, SOFTWARE PROGRAM, AND MEASUREMENT ARRANGEMENT

摘要

The invention relates to method for determining a relative change in a sap flow density in a vascular plant (1). The method comprises the steps:- arranging a first electrode (4) and a second electrode (5) in the vascular plant (1) to determine an electrical impedance of xylem tissue (3) of the vascular plant (1);- either applying an alternating probe voltage (12) over the first and second electrodes (4, 5) and measuring a resulting current (13) flowing from one of the first and second electrodes (4, 5) to the other of the first and second electrodes (4, 5) or applying an alternating probe current flowing from one of the first and second electrodes (4, 5) to the other of the first and second electrodes (4, 5) and measuring a resulting voltage over the first and second electrodes (4, 5);- monitoring a thermal state in the xylem tissue (3) while applying either the alternating probe voltage (12) or the alternating probe current;- calculating from either the applied alternating probe voltage (12) and the measured resulting current (13) or the applied alternating probe current and the measured resulting voltage a magnitude of the electrical impedance (31) of the xylem tissue (3), wherein an influence of the thermal state of the xylem tissue (3) on the magnitude of the electrical impedance (31) is accounted for; and- determining the relative change in the sap flow density in the vascular plant (3) by using a relation between the sap flow density and the magnitude of the electrical impedance (31) that an increased sap flow density results in an increased magnitude of the electrical impedance (31).;Other aspects of the invention are a software program realizing the method and a measurement arrangement for determining the relative change in the sap flow density in the vascular plant (1).