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Monoterpene ‘ thermometer ’ of tropical forest‐atmosphere response to climate warming
Author(s) -
Jardine Kolby J.,
Jardine Angela B.,
Holm Jennifer A.,
Lombardozzi Danica L.,
NegronJuarez Robinson I.,
Martin Scot T.,
Beller Harry R.,
Gimenez Bruno O.,
Higuchi Niro,
Chambers Jeffrey Q.
Publication year - 2017
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12879
Subject(s) - monoterpene , atmospheric sciences , environmental science , photosynthesis , atmosphere (unit) , carbon cycle , chemistry , biosphere , climatology , botany , ecology , ecosystem , biology , meteorology , geography , physics , geology
Tropical forests absorb large amounts of atmospheric CO 2 through photosynthesis but elevated temperatures suppress this absorption and promote monoterpene emissions. Using 13 CO 2 labeling, here we show that monoterpene emissions from tropical leaves derive from recent photosynthesis and demonstrate distinct temperature optima for five groups (Groups 1–5), potentially corresponding to different enzymatic temperature‐dependent reaction mechanisms within β ‐ocimene synthases. As diurnal and seasonal leaf temperatures increased during the Amazonian 2015 El Niño event, leaf and landscape monoterpene emissions showed strong linear enrichments of β ‐ocimenes (+4.4% °C −1 ) at the expense of other monoterpene isomers. The observed inverse temperature response of α ‐pinene (−0.8% °C −1 ), typically assumed to be the dominant monoterpene with moderate reactivity, was not accurately simulated by current global emission models. Given that β ‐ocimenes are highly reactive with respect to both atmospheric and biological oxidants, the results suggest that highly reactive β ‐ocimenes may play important roles in the thermotolerance of photosynthesis by functioning as effective antioxidants within plants and as efficient atmospheric precursors of secondary organic aerosols. Thus, monoterpene composition may represent a new sensitive ‘thermometer’ of leaf oxidative stress and atmospheric reactivity, and therefore a new tool in future studies of warming impacts on tropical biosphere‐atmosphere carbon‐cycle feedbacks.