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| Titel |
Laboratory and field measurements of enantiomeric monoterpenes in plant emissions |
| VerfasserIn |
Wei Song, Michael Staudt, Noureddine Yassaa, Jonathan Williams |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250050910
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| Zusammenfassung |
| Monoterpenes are an important class of biogenic volatile organic compounds in the
troposphere. Several monoterpenes exist in two mirror image (enantiomeric) forms e.g.
(+)-α–pinene and (-)-α-pinene. These enantiomeric ratios of monoterpenes have been shown
previously to be useful in source characterization and to exhibit distinct regional
chemodiversity. In this study we investigate the enantiomeric distribution of monoterpenes in
the emissions from three different species namely: Quercus ilex, Rosmarinus officinalis,
Pinus halepensis. Quercus ilex was selected as it generates monoterpenes depending on
light, while in contrast the Pinus halepensis and Rosmarinus officinalis store the
monoterpenes in resin ducts and trichomes respectively. The enantiomeric ratio of α-pinene
was investigated in the laboratory as a function of temperature (20 to 45Ë C) and
light (0 to 1600 PAR). Rosmarinus officinalis showed predominant (+)-α-pinene
emissions, consistent with previous studies. Quercus ilex and Pinus halepensis species
exhibited both (-) and (+) dominant species emission. It was noted generally that for
species with predominately (-)-α-pinene emissions, the enatiomeric ratio showed a
distinct light dependence. A comparison is made to ambient data collected over a
homogeneous Quercus ilex forest in Montpellier, France, and to a Boreal forest Hyytiälä,
Finland. A clear diurnal cycle in the enantiomeric ratio was observed above the French
forest, with (-)-α-pinene predominance in the morning and evening but becoming
(+)-α-pinene dominant around midday. However this tendency was reversed in the
Boreal forest, the enantiomeric ratio became richer in (-)-α-pinene around midday. |
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