References

Biogeosciences

1726-4189

Copernicus Publications

Göttingen, Germany

10.5194/bg-11-1435-2014

Laboratory and field measurements of enantiomeric monoterpene emissions as a function of chemotype, light and temperature

Song

¹ Staudt

² Bourgeois

² Williams

Max Planck Institut für Chemie, Hahn Meitner Weg 1, 55128 Mainz, Germany

Centre d'Ecologie Fonctionnelle et Evolutive (UMR5175), 1919 Route de Mende, 34293 Montpellier CEDEX 5, France

14 03 2014

11 5 1435 1447

2014

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

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The full text article is available as a PDF file from https://bg.copernicus.org/articles/11/1435/2014/bg-11-1435-2014.pdf

Plants emit significant amounts of monoterpenes into the earth's atmosphere, where they react rapidly to form a multitude of gas phase species and particles. Many monoterpenes exist in mirror-image forms or enantiomers. In this study the enantiomeric monoterpene profile for several representative plants (Quercus ilex L., Rosmarinus officinalis L., and Pinus halepensis Mill.) was investigated as a function of chemotype, light and temperature both in the laboratory and in the field. Analysis of enantiomeric monoterpenes from 19 Quercus ilex individuals from Southern France and Spain revealed four regiospecific chemotypes (genetically fixed emission patterns). In agreement with previous work, only Quercus ilex emissions increased strongly with light. However, for all three plant species no consistent enantiomeric variation was observed as a function of light, and the enantiomeric ratio of α-pinene was found to vary by less than 20% from 100 and 1000 μmol m−2 s−1 PAR (photosynthetically active radiation). The rate of monoterpene emission increased with temperature from all three plant species, but little variation in the enantiomeric distribution of α-pinene was observed with temperature. There was more enantiomeric variability between individuals of the same species than could be induced by either light or temperature. Field measurements of α-pinene enantiomer mixing ratios in the air, taken at a Quercus ilex forest in Southern France, and several other previously reported field enantiomeric ratio diel cycle profiles are compared. All show smoothly varying diel cycles (some positive and some negative) even over changing wind directions. This is surprising in comparison with variations of enantiomeric emission patterns shown by individuals of the same species.

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