Proximal Remote Sensing-Based Vegetation Indices for Monitoring Mango Tree Stem Sap Flux Density

Plant water use is an important function reflecting vegetation physiological status and affects plant growth, productivity, crop/fruit quality. Although hyperspectral indices have recently been proposed to assess use, limited sample sizes for established models greatly astricts their wide applications. In this study, we managed gather a large volume of continuous measurements canopy spectra through proximally set spectroradiometers over the canopy, enabling us investigate feasibility using narrow-band trace canopy-scale indicated by stem sap flux density measured with flow sensors. The results proved that newly developed D (520, 560) index was optimal capture variation under clear sky conditions (R2 = 0.53), while best identified non-clear (530, 575) 0.32). Furthermore, bands used in these agreed reported sensitive estimating leaf stomatal conductance which has critical role transpiration rate regulation short time period. Our should point way towards proximal tree directly.