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Plant functional traits and canopy structure control the relationship between photosynthetic CO 2 uptake and far‐red sun‐induced fluorescence in a Mediterranean grassland under different nutrient availability

2017; Wiley; Volume: 214; Issue: 3 Linguagem: Inglês

10.1111/nph.14437

1469-8137

Mirco Migliavacca, Óscar Pérez‐Priego, Micol Rossini, Tarek S. El‐Madany, Gerardo Moreno, Christiaan van der Tol, Uwe Rascher, Anna Berninger, Verena Bessenbacher, Andreas Burkart, Arnaud Carrara, Francesco Fava, Jin‐Hong Guan, Tiana Hammer, Kathrin Henkel, Enrique Juárez, Tommaso Julitta, Olaf Kolle, M. Pilar Martín, Talie Musavi, Javier Pacheco‐Labrador, Andrea Pérez‐Burgueño, Thomas Wutzler, Sönke Zaehle, Markus Reichstein,

Remote Sensing in Agriculture

Sun-induced fluorescence (SIF) in the far-red region provides a new noninvasive measurement approach that has the potential to quantify dynamic changes in light-use efficiency and gross primary production (GPP). However, the mechanistic link between GPP and SIF is not completely understood. We analyzed the structural and functional factors controlling the emission of SIF at 760 nm (F760 ) in a Mediterranean grassland manipulated with nutrient addition of nitrogen (N), phosphorous (P) or nitrogen-phosphorous (NP). Using the soil-canopy observation of photosynthesis and energy (SCOPE) model, we investigated how nutrient-induced changes in canopy structure (i.e. changes in plant forms abundance that influence leaf inclination distribution function, LIDF) and functional traits (e.g. N content in dry mass of leaves, N%, Chlorophyll a+b concentration (Cab) and maximum carboxylation capacity (Vcmax )) affected the observed linear relationship between F760 and GPP. We conclude that the addition of nutrients imposed a change in the abundance of different plant forms and biochemistry of the canopy that controls F760 . Changes in canopy structure mainly control the GPP-F760 relationship, with a secondary effect of Cab and Vcmax . In order to exploit F760 data to model GPP at the global/regional scale, canopy structural variability, biodiversity and functional traits are important factors that have to be considered.