期刊
ENVIRONMENTAL AND EXPERIMENTAL BOTANY
卷 72, 期 3, 页码 377-386出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.envexpbot.2010.11.006
关键词
Isoprene; Monoterpenes; Sesquiterpenes; Volatile organic compounds; Near-infrared spectroscopy; Temperature
资金
- Emil Aaltonen Foundation
- Danish Council for Independent Research | Natural Sciences
- EU [Fp6 506004]
- Abisko Scientific Research Station
Climate change is exposing arctic ecosystems to higher temperature, increased nutrient availability and shading due to the increasing cloud cover and the expanding forests. In this work, we assessed how these factors affect the emissions of biogenic volatile organic compounds (BVOCs) from three subarctic dwarf shrub species in a field experiment after 18 treatment years. Of the studied species the willow Salix phylicifolia L. was the only isoprene-emitter with an emission potential of 16.1 +/- 8.4 mu g g(-1) dw h(-1) (at 30 degrees C and photosynthetic photon flux density of 1000 mu mol m(-2) s(-1)). The dwarf birch Betula nana L. had significant emissions of various reactive BVOCs, including monoterpenes and sesquiterpenes. The evergreen Cassiope tetragona (L) D. Don emitted high amounts of mono- and sesquiterpenes. Due to chance, the temperature in the warming treatment (employing open-top plastic tents) and the unwarmed treatments was similar at the time of the measurements, and therefore long-term indirect effects of warming could be assessed without interference of temperature differences at the time of measurement. The long-term warming had not altered foliar N, P or condensed tannin concentrations, but it had led to other chemical changes detected in the near-infrared reflectance spectra of the leaves. Nevertheless, there were no significant differences in the BVOC emissions per unit leaf mass measured by the dynamic enclosure method and gas chromatography-mass spectrometry. Annual additions of NPK fertilizer, which mimicked increased nutrient availability, had accumulated P in the leaves of all species. In addition, fertilization marginally increased the leaf N concentration of B. nana. The only significant fertilization effect on BVOC emissions was a stimulation of emission of the sesquiterpene beta-selinene from S. phylicifolia. The shading treatment obtained by dome-shaped hessian tents did not cause clear long-term changes in leaf chemistry or BVOC emissions. The only observed change was a marginally significant increase in sesquiterpene emissions from B. nana. when the treatment effects on long-term biomass changes in the different treatments were taken into account by proportioning the BVOC emissions to the biomass of each species in the field treatments, warming led to a significant increase and shading to a decrease in the total BVOC emissions per unit ground area from B. nano. These results highlight the importance of an integrated approach for realistic assessment of responses to climate change. (C) 2010 Elsevier B.V. All rights reserved.
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