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On the Functional Relationship Between Fluorescence and Photochemical Yields in Complex Evergreen Needleleaf Canopies
Author(s) -
Maguire Andrew J.,
Eitel Jan U. H.,
Griffin Kevin L.,
Magney Troy S.,
Long Ryan A.,
Vierling Lee A.,
Schmiege Stephanie C.,
Jennewein Jyoti S.,
Weygint William A.,
Boelman Natalie T.,
Bruner Sarah G.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087858
Subject(s) - irradiance , chlorophyll fluorescence , environmental science , context (archaeology) , fluorescence , atmospheric sciences , evergreen , canopy , solar irradiance , photochemistry , biological system , chemistry , ecology , biology , physics , optics , paleontology
Recent advancements in understanding remotely sensed solar‐induced chlorophyll fluorescence often suggest a linear relationship with gross primary productivity at large spatial scales. However, the quantum yields of fluorescence and photochemistry are not linearly related, and this relationship is largely driven by irradiance. This raises questions about the mechanistic basis of observed linearity from complex canopies that experience heterogeneous irradiance regimes at subcanopy scales. We present empirical data from two evergreen forest sites that demonstrate a nonlinear relationship between needle‐scale observations of steady‐state fluorescence yield and photochemical yield under ambient irradiance. We show that accounting for subcanopy and diurnal patterns of irradiance can help identify the physiological constraints on needle‐scale fluorescence at 70–80% accuracy. Our findings are placed in the context of how solar‐induced chlorophyll fluorescence observations from spaceborne sensors relate to diurnal variation in canopy‐scale physiology.