Non-Destructive Near-Infrared Sensor Method for Measuring Water Content of Intact Eggplant Leaves

Abstract

The objective of this study was to evaluate the ability of a hand-held near-infrared (NIR) sensor and water absorption index to estimate the water content in intact eggplant leaves using a pot experiment. The NIR spectroscopy using a sin-gle wavelength (1940 nm) has already been used to estimate the water content of detached samples in a laboratory. However, it is not known whether this method can be used to estimate the water content of intact leaves of living plants. Therefore, we attempted to compare this method with destructive method by simulating drought stress and analyzing the relationship between leaf water content and soil matric potential. The water content of intact eggplant leaves was predict-ed with a calibration model using NIR reflectance. Both the measured and predicted water content of leaves decreased with decreasing soil matric potential. These results show that both destructive and NIR measurements can be used to estimate the water stress condition. Based on these findings, a hand-held NIR sensor is useful for estimating the water content of intact leaves of living plants.