Medidor de fluxo de seiva com balanço de calor caulinar.

Abstract

Methods to measure the sap flow in plants are important for the agricultural practice in irrigated areas and for plant physiology studies. This report describes the research undertaken to design and to build a sap flow measuring device with a datalogger that is based on the method to determine stem heat budget under constant heating conditions. The performance of the instrument prototype was tested using a plant stem simulator consisting of a plastic tube (20 mm diameter) filled with cellulose fiber through which water flowed at a known flow rate. The water flow measured by the instrument in this experiment was always within 10% of the known water flow value. Another performance test was done comparing the sap flow measured by the instrument for a plant with a 20 mm stem diameter and the value obtained by a weighting lysimeter. This experiment indicated that the instrument measured sap flow values were also always within a 10% range of the sap flow readings provided by the lysimeter. The experimental results obtained by the prototype developed from this research indicate that the instrument can be effectively used in agricultural field applications.