Location: Crops Pathology and Genetics ResearchTitle: Modification of a gas exchange system to measure active and passive chlorophyll fluorescence simultaneously under field conditions
|MEEKER, ELIOT - University Of California, Davis
|MAGNEY, TROY - University Of California, Davis
|BAMBACH, NICOLAS - University Of California, Davis
|MOMAYYEZI, MINA - University Of California, Davis
Submitted to: AoB Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2020
Publication Date: 12/6/2020
Citation: Meeker, E.W., Magney, T.S., Bambach, N., Momayyezi, M., McElrone, A.J. 2020. Modification of a gas exchange system to measure active and passive chlorophyll fluorescence simultaneously under field conditions. AoB Plants. 13(1). Article plaa006. https://doi.org/10.1093/aobpla/plaa066.
Technical Abstract: An LI-6800 gas exchange instrument was modified with a Flame VIS-NIR spectrometer to measure active and passive fluorescence simultaneously. The system was designed by drilling a hole into the bottom plate of the leaf chamber and inserting a fiber optic to measure solar-induced fluorescence (SIF) from the abaxial surface of a leaf. This new set-up can concurrently measure gas exchange, passive fluorescence, and active fluorescence over the same leaf area and will allow researchers to measure leaf-level SIF in the field to validate tower-based and satellite measurements. To test the modified instrument, measurements were performed on well-watered and water stressed walnut trees at three light-levels and a constant temperature. Measurements on these same plants were also performed with a similarly modified GFS-3000 gas exchange instrument to compare results. We found a positive linear correlation between the SIF measurements of the modified LI-6800 and GFS-3000 instruments. We also report a positive linear relationship between the SIF and the normalized steady-state chlorophyll fluorescence (Fs/Fo) from the PAM fluorometer of the LI-6800 system. Accordingly, this modification will inform the link between spectrally resolved SIF and gas-exchange – leading to improved interpretation of how SIF tracks changes in the light reactions of photosynthesis.