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Results for “chlorophyll fluorescence”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Potential of hotspot solar‐induced chlorophyll fluorescence for better tracking terrestrial photosynthesis

Abstract Remote sensing of solar‐induced fluorescence (SIF) opens a new window for quantifying a key ecological variable, the terrestrial ecosystem gross primary production (GPP), because of the revealed strong SIF–GPP correlation. However, similar to many other remotely sensed metrics, SIF observations suffer from the sun‐sensor geometry effects, which may have important impacts on the SIF–GPP relationship but remain poorly understood. Here we used remotely sensed SIF, globally distributed tower GPP data, and a mechanistic model to provide a systematic analysis. Our results reveal that leaf physiology, canopy structure, and sun‐sensor geometries all affect the SIF–GPP relationship. In particular, we found that SIF observations in the sun‐tracking hotspot direction can be a better proxy of GPP due to the similar responses of light use efficiency and SIF escaping probability in the hotspot direction to the increasing incoming solar radiation. Such conclusions are supported by a variety of modeling simulations and satellite observations over various plant function types, at different time scales and with satellite observational modes. This study demonstrates the potential and advantage of normalizing SIF observations to the hotspot direction for better global GPP estimations. This study also demonstrates the great potentials of current and future spaceborne sun‐tracking satellite missions for a significant improvement in measuring and monitoring, at a wide range of spatial and temporal scales, the changes in terrestrial ecosystem GPP in response to anticipated changes in the Earth's environmental conditions.

Hao, Dalei↗
DOE OSTI2021

Isoprene, Chlorophyll fluorescence, and leaf temperature data from Manaus, Brazil, 2017 - 2018

The data included in this data package are a demonstration of an inverse relationship in the early successional species Vismia guianensis in the central Amazon between stomatal conductance (gs) and leaf temperature, while net photosynthesis (Pn) showed an optimum value of 32.6 ± 0.4°C. In contrast to Pn, photosynthetic electron transport rates (ETR) and the QA oxidation state (qL) increased linearly with leaf temperature. Leaf isoprene emissions, a primary product of photosynthesis and strongly linked to plant high temperature stress tolerance, showed strong linear correlations with ETR (ƿ = 0.98) and qL (ƿ = 0.99). Furthermore, inhibition of isoprenoid biosynthesis repressed Pn at high temperatures through a mechanism that was independent of stomatal closure. Data is used in the publication, "Stimulation of isoprene emissions and electron transport rates as a key mechanism of thermal tolerance in the tropical species Vismia guianensis." See the below Dataset References field for the full citation.

54 ENVIRONMENTAL SCIENCES↗