title: Leaf anatomy, BVOC emission and CO2 exchange of arctic plants following snow addition and summer warming.
abstract: OBJECTIVE
  Climate change in the Arctic is projected to increase temperature, precipitation and snowfall. This may alter leaf anatomy and gas exchange either directly or indirectly. Our aim was to assess whether increased snow depth and warming modify leaf anatomy and affect biogenic volatile organic compound (BVOC) emissions and CO2exchange of the widespread arctic shrubs Betula nana and Empetrum nigrum ssp. hermaphroditum METHODS: Measurements were conducted in a full-factorial field experiment in Central West Greenland, with passive summer warming by open-top chambers and snow addition using snow fences. Leaf anatomy was assessed using light microscopy and scanning electron microscopy. BVOC emissions were measured using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analysed by gas chromatography-mass spectrometry. Carbon dioxide exchange was measured using an infrared gas analyser.
  
  
  RESULTS
  Despite a later snowmelt and reduced photosynthesis for B. nana especially, no apparent delays in the BVOC emissions were observed in response to snow addition. Only a few effects of the treatments were seen for the BVOC emissions, with sesquiterpenes being the most responsive compound group. Snow addition affected leaf anatomy by increasing the glandular trichome density in B. nana and modifying the mesophyll of E. hermaphroditum The open-top chambers thickened the epidermis of B. nana, while increasing the glandular trichome density and reducing the palisade:spongy mesophyll ratio in E. hermaphroditum CONCLUSIONS: Leaf anatomy was modified by both treatments already after the first winter and we suggest links between leaf anatomy, CO2exchange and BVOC emissions. While warming is likely to reduce soil moisture, melt water from a deeper snow pack alleviates water stress in the early growing season. The study emphasizes the ecological importance of changes in winter precipitation in the Arctic, which can interact with climate-warming effects.
authors.affiliation: Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.|Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
authors.forename: Michelle
authors.initials: M
authors.lastname: Schollert
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Kivimäenpää
authors.affiliation: Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.|Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Michelsen
authors.affiliation: Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62 Lund, Sweden.
authors.forename: Daan
authors.initials: D
authors.lastname: Blok
authors.affiliation: Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark riikkar@bio.ku.dk.|Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
authors.forename: Riikka
authors.initials: R
authors.lastname: Rinnan
mesh_terms: D001110:Arctic Regions; D029662:Betula / Q000033:anatomy & histology* / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D002245:Carbon Dioxide / Q000378:metabolism*; D029791:Ericaceae / Q000033:anatomy & histology* / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D006116:Greenland; D006358:Hot Temperature; D008853:Microscopy; D008855:Microscopy, Electron, Scanning; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D012621:Seasons; D012914:Snow; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D055549:Volatile Organic Compounds; D002245:Carbon Dioxide
keywords: BVOC; Betula nana; CO2 exchange; Empetrum nigrum; biogenic volatile organic compounds; climate change; microscopy; monoterpene; open-top chamber; sesquiterpene; snow; temperature