2020/06/25 by Julia Marrs, J. K. Marrs, Jaret S. Reblin +11 · 138 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Environmental Science · #Atmospheric sciences #Biology #Botany #Carbon assimilation #Carbon cycle #Chemistry #Chlorophyll fluorescence #Ecology #Ecosystem #Environmental science #Fluorescence #Optics #Photosynthesis #Photosynthetic Processes and Mechanisms #Physics #Plant Water Relations and Carbon Dynamics #Remote Sensing in Agriculture #Stomatal conductance
paper · pdf · doi:10.1029/2020gl087956
published in Geophysical Research Letters 47(15) (American Geophysical Union)
openalex publication_date 2020/06/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Since 2006, six satellites measuring solar‐induced chlorophyll fluorescence (SIF) have been launched to better constrain terrestrial gross primary productivity (GPP). The promise of the SIF signal as a proxy for photosynthesis with a strong relationship to GPP has been widely cited in carbon cycling studies. However, chlorophyll fluorescence originates from dynamic energy partitioning at the leaf level and does not exhibit a uniformly linear relationship with photosynthesis at finer scales. We induced stomatal closure in deciduous woody tree branches and measured SIF at a proximal scale, alongside leaf‐level gas exchange, pulse amplitude modulated (PAM) fluorescence, and leaf pigment content. We found no change in SIF or steady‐state PAM fluorescence, despite clear reductions in stomatal conductance, carbon assimilation, and light‐use efficiency in treated leaves. These findings suggest that equating SIF and photosynthesis is an oversimplification that may undermine the utility of SIF as a biophysical parameter in GPP models.