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Dynamics of sun-induced chlorophyll fluorescence and reflectance to detect stress-induced variations in canopy photosynthesis |
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| Authors: | Francisco Pinto Marco Celesti Kelvin Acebron Giorgio Alberti Sergio Cogliati Roberto Colombo Radosław Juszczak Shizue Matsubara Franco Miglietta Angelo Palombo Cinzia Panigada Stefano Pignatti Micol Rossini Karolina Sakowska Anke Schickling Dirk Schüttemeyer Marcin Stróżecki Marin Tudoroiu Uwe Rascher |
| Affiliation: | 1. Institute of Bio and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany;2. Remote Sensing of Environmental Dynamics Laboratory, Department of Earth and Environmental Sciences (DISAT), University of Milano-Bicocca, Milan, Italy;3. Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy Institute of BioEconomy (IBE), National Research Council (CNR), Rome, Italy;4. Meteorology Department, Poznan University of Life Sciences, Poznań, Poland;5. Institute of BioEconomy (IBE), National Research Council (CNR), Rome, Italy FoxLab Joint CNR-FEM Initiative, San Michele all'Adige, Italy;6. Institute of Methodologies for Environmental Analysis (IMAA), National Research Council (CNR), Rome, Italy;7. Institute of BioEconomy (IBE), National Research Council (CNR), Rome, Italy;8. European Space Agency (ESA), ESTEC, Noordwijk, The Netherlands;9. Institute of BioEconomy (IBE), National Research Council (CNR), Rome, Italy European Space Agency (ESA), ESTEC, Noordwijk, The Netherlands University of Natural Resources and Life Sciences, Vienna, Austria |
| Abstract: | Passive measurement of sun-induced chlorophyll fluorescence (F) represents the most promising tool to quantify changes in photosynthetic functioning on a large scale. However, the complex relationship between this signal and other photosynthesis-related processes restricts its interpretation under stress conditions. To address this issue, we conducted a field campaign by combining daily airborne and ground-based measurements of F (normalized to photosynthetically active radiation), reflectance and surface temperature and related the observed changes to stress-induced variations in photosynthesis. A lawn carpet was sprayed with different doses of the herbicide Dicuran. Canopy-level measurements of gross primary productivity indicated dosage-dependent inhibition of photosynthesis by the herbicide. Dosage-dependent changes in normalized F were also detected. After spraying, we first observed a rapid increase in normalized F and in the Photochemical Reflectance Index, possibly due to the blockage of electron transport by Dicuran and the resultant impairment of xanthophyll-mediated non-photochemical quenching. This initial increase was followed by a gradual decrease in both signals, which coincided with a decline in pigment-related reflectance indices. In parallel, we also detected a canopy temperature increase after the treatment. These results demonstrate the potential of using F coupled with relevant reflectance indices to estimate stress-induced changes in canopy photosynthesis. |
| Keywords: | canopy temperature Dicuran photochemical reflectance index photosynthesis sun-induced chlorophyll fluorescence |