Simultaneous leaf-level measurement of trace gas emissions and photosynthesis with a portable photosynthesis system
<p>Plants emit considerable quantities of volatile organic compounds (VOCs), the identity and amount of which vary with temperature, light, and other environmental factors. Portable photosynthesis systems are a useful method for simultaneously quantifying in situ leaf-level emissions of VOCs a...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2020-08-01
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Series: | Atmospheric Measurement Techniques |
Online Access: | https://amt.copernicus.org/articles/13/4123/2020/amt-13-4123-2020.pdf |
Summary: | <p>Plants emit considerable quantities of volatile organic
compounds (VOCs), the identity and amount of which vary with temperature,
light, and other environmental factors. Portable photosynthesis systems are a
useful method for simultaneously quantifying in situ leaf-level emissions of
VOCs and plant physiology. We present a comprehensive characterization of
the LI-6800 portable photosynthesis system's ability to be coupled to trace
gas detectors and measure leaf-level trace gas emissions, including limits
in flow rates, environmental parameters, and VOC backgrounds. Instrument
contaminants from the LI-6800 can be substantial but are dominantly complex
molecules such as siloxanes that are structurally dissimilar to biogenic
VOCs and thus unlikely to interfere with most leaf-level emissions
measurements. We validate the method by comparing <span class="inline-formula">CO<sub>2</sub></span> assimilation
calculated internally by the portable photosynthesis system to measurements
taken with an external <span class="inline-formula">CO<sub>2</sub></span> gas analyzer; these assimilation
measurements agree within 1 %. We also demonstrate both online and
offline measurements of plant trace gas exchange using the LI-6800. Offline
measurements by pre-concentration on adsorbent cartridges enable the detection
of a broad suite of VOCs, including monoterpenes (e.g., limonene) and
aldehydes (e.g., decanal). Online measurements can be more challenging if
flow rates require dilution with ultrapure zero air. We use high-resolution
time-of-flight chemical ionization mass spectrometry coupled to the LI-6800
to measure the direct plant emission of formic acid.</p> |
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ISSN: | 1867-1381 1867-8548 |