Heat Transfer-Based Monitoring System for Sap Flow in Plants

Sap flow, the movement of water and nutrients through the vascular tissues of plants, is closely associated with key physiological processes such as photosynthesis and transpiration. Monitoring of sap flow is essential for understanding plant health and optimizing agricultural practices. However, conventional sap flow sensors are often rigid and invasive, making them incompatible with the soft, curved surfaces of plant stems and petioles. In this study, we propose a new thermal-based sap flow sensor capable of non-invasive, real-time monitoring. Through heat conduction simulations and controlled experiments, we demonstrate that the downstream temperature of the sensor decreases as flow rate increases, establishing a negative correlation between temperature and sap flow.