Unraveling the physical and physiological basis for the solar- induced chlorophyll fluorescence and photosynthesis relationship using continuous leaf and canopy measurements of a corn crop

Yang, Peiqi; Tol, Christiaan Van der; Campbell, Petya Entcheva; Middleton, Elizabeth M.

Unraveling the physical and physiological basis for the solar- induced chlorophyll fluorescence and photosynthesis relationship using continuous leaf and canopy measurements of a corn crop

dc.contributor.author	Yang, Peiqi
dc.contributor.author	Tol, Christiaan Van der
dc.contributor.author	Campbell, Petya Entcheva
dc.contributor.author	Middleton, Elizabeth M.
dc.date.accessioned	2020-10-07T17:17:51Z
dc.date.available	2020-10-07T17:17:51Z
dc.date.issued	2021-01-20
dc.description.abstract	Estimates of the gross terrestrial carbon uptake exhibit large uncertainties. Sun-induced chlorophyll fluorescence (SIF) has an apparent near-linear relationship with gross primary production (GPP). This relationship will potentially facilitate the monitoring of photosynthesis from space. However, the exact mechanistic connection between SIF and GPP is still not clear. To explore the physical and physiological basis for their relationship, we used a unique data set comprising continuous field measurements of leaf and canopy fluorescence and photosynthesis of corn over a growing season. We found that, at canopy scale, the positive relationship between SIF and GPP was dominated by absorbed photosynthetically active radiation (APAR), which was equally affected by variations in incoming radiation and changes in canopy structure. After statistically controlling these underlying physical effects, the remaining correlation between far-red SIF and GPP due solely to the functional link between fluorescence and photosynthesis at the photochemical level was much weaker (ρ=0.30). Active leaf level fluorescence measurements revealed a moderate positive correlation between the efficiencies of fluorescence emission and photochemistry for sunlit leaves in well-illuminated conditions but a weak negative correlation in the low-light condition, which was negligible for shaded leaves. Differentiating sunlit and shaded leaves in the light use efficiency (LUE) models for SIF and GPP facilitates a better understanding of the SIF–GPP relationship at different environmental and canopy conditions. Leaf level fluorescence measurements also demonstrated that the sustained thermal dissipation efficiency dominated the seasonal energy partitioning, while the reversible heat dissipation dominated the diurnal leaf energy partitioning. These diurnal and seasonal variations in heat dissipation underlie, and are thus responsible for, the observed remote-sensing-based link between far-red SIF and GPP.	en_US
dc.description.sponsorship	This work was supported by the Netherlands Organization for Scientific Research, grant ALWGO.2017.018. The collection of field data and the work of co-authors Campbell and Middleton were supported by NASA's Terrestrial Ecology program grant 80NSSC19M0110, Land Cover Land Use Change grant 80NSSC18K0337, and the Biospherc-Sciences Laboratory at NASA Goddard Space Flight Center.	en_US
dc.description.uri	https://bg.copernicus.org/articles/18/441/2021/	en_US
dc.format.extent	25 pages	en_US
dc.genre	journal articles	en_US
dc.identifier	doi:10.13016/m22c5w-2hqk
dc.identifier.citation	Yang, P., van der Tol, C., Campbell, P. K. E., and Middleton, E. M.: Unraveling the physical and physiological basis for the solar- induced chlorophyll fluorescence and photosynthesis relationship using continuous leaf and canopy measurements of a corn crop, Biogeosciences, 18, 441–465, https://doi.org/10.5194/bg-18-441-2021, 2021.	en_US
dc.identifier.uri	https://doi.org/10.5194/bg-18-441-2021
dc.identifier.uri	http://hdl.handle.net/11603/19753
dc.language.iso	en_US	en_US
dc.publisher	EGU	en_US
dc.relation.isAvailableAt	The University of Maryland, Baltimore County (UMBC)
dc.relation.ispartof	UMBC Joint Center for Earth Systems Technology
dc.relation.ispartof	UMBC Faculty Collection
dc.relation.ispartof	UMBC Physics Department
dc.rights	This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
dc.rights	Attribution 4.0 International	*
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	*
dc.title	Unraveling the physical and physiological basis for the solar- induced chlorophyll fluorescence and photosynthesis relationship using continuous leaf and canopy measurements of a corn crop	en_US
dc.type	Text	en_US
dcterms.creator	https://orcid.org/0000-0002-0505-4951