title: Respiratory flexibility and efficiency are affected by simulated global change in Arctic plants.
abstract: Laboratory studies indicate that, in response to environmental conditions, plants modulate respiratory electron partitioning between the 'energy-wasteful' alternative pathway (AP) and the 'energy-conserving' cytochrome pathway (CP). Field data, however, are scarce. Here we investigate how 20-yr field manipulations simulating global change affected electron partitioning in Alaskan Arctic tundra species. We sampled leaves from three dominant tundra species - Betula nana, Eriophorum vaginatum and Rubus chamaemorus - that had been strongly affected by manipulations of soil nutrients, light availability, and warming. We measured foliar dark respiration, in-vivo electron partitioning and alternative oxidase/cytochrome c oxidase concentrations in addition to leaf traits and mitochondrial ultrastructure. Changes in leaf traits and ultrastructure were similar across species. Respiration at 20°C (R(20)) was reduced 15% in all three species grown at elevated temperature, suggesting thermal acclimation of respiration. In Betula, the species with the largest growth response to added nutrients, CP activity increased from 9.4 ± 0.8 to 16.6 ± 1.6 nmol O(2) g(-1) DM s(-1) whereas AP activity was unchanged. The ability of Betula to selectively increase CP activity in response to the environment may contribute to its overall ecological success by increasing respiratory energy efficiency, and thus retaining more carbon for growth.
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.
authors.forename: Ari
authors.initials: A
authors.lastname: Kornfeld
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, 10027, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Heskel
authors.affiliation: Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia.
authors.forename: Owen K
authors.initials: OK
authors.lastname: Atkin
authors.affiliation: Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Gough
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, 10027, USA.|Department of Earth and Environmental Sciences, Columbia University, New York, NY, 10027, USA.|Lamont-Doherty Earth Observatory, Columbia University, 61 Rt 9W, Palisades, NY, 10964, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Griffin
authors.affiliation: Department of Geological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.
authors.forename: Travis W
authors.initials: TW
authors.lastname: Horton
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Turnbull
mesh_terms: D000064:Acclimatization; D001110:Arctic Regions; D029662:Betula / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D002245:Carbon Dioxide / Q000378:metabolism*; D057231:Climate Change; D029785:Cyperaceae / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D003580:Cytochromes / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism; D027824:Rosaceae / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D013696:Temperature; D000099188:Alternative Oxidase
chemical_list: D002245:Carbon Dioxide; D003580:Cytochromes; D003576:Electron Transport Complex IV; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase