Comparing the quantum use efficiency of red and far-red sun-induced fluorescence at leaf and canopy under heat-drought stress

作者：Sebastian Wieneke, Javier Pacheco‐Labrador, Miguel D. Mahecha, Sílvia Poblador, Sara Vicca, Ivan A. Janssens · 发表于：Remote Sensing of Environment · 年份：2024 · DOI：10.1016/j.rse.2024.114294 · 被引用次数：26 · 研究领域：Remote Sensing in Agriculture、Light effects on plants、Plant responses to elevated CO2

Sun-Induced chlorophyll Fluorescence (SIF) is the most promising remote sensing signal to monitor photosynthesis in space and time. However, under stress conditions its interpretation is often complicated by factors such as light absorption and plant morphological and physiological adaptations. To ultimately derive the quantum yield of fluorescence (ΦF) at the photosystem from canopy measurements, the so-called escape probability (fesc) needs to be accounted for. In this study, we aim to compare ΦF measured at leaf- and canopy-scale to evaluate the influence of stress responses on the two signals based on a potato mesocosm heat-drought experiment. First, we compared the performance of recently proposed reflectance-based approaches to estimate leaf and canopy red fesc using data-supported simulations of the radiative transfer model SCOPE. While the leaf red fesc showed a strong correlation (r2 ≥ 0.76), the canopy red fesc exhibited no relationship with the SCOPE retrieved red fesc in our experiment. We therefore propose modifications to the canopy model to address this limitation. We then used the modified models of red fesc, along with an existing model for far-red fesc to analyse the dynamics of leaf and canopy red and far-red fluorescence under increasing drought and heat stress conditions. By incorporating fesc, we obtained a closer agreement between leaf and canopy measurements. Specifically, for red fesc, the r2 of the two variables increased from 0.3 to 0.50, and for fa...