title: Boreal and temperate trees show strong acclimation of respiration to warming.
abstract: Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.|Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2753, Australia.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Reich
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.
authors.forename: Kerrie M
authors.initials: KM
authors.lastname: Sendall
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.
authors.forename: Artur
authors.initials: A
authors.lastname: Stefanski
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.|State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.|Smithsonian Environmental Research Center, Edgewater, Maryland 20137, USA.
authors.forename: Roy L
authors.initials: RL
authors.lastname: Rich
authors.affiliation: Department of Forest Resources, University of Minnesota, Minnesota 55108, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Montgomery
mesh_terms: D000064:Acclimatization; D001272:Atmosphere; D002245:Carbon Dioxide / Q000378:metabolism; D019069:Cell Respiration; D003624:Darkness; D017753:Ecosystem; D065928:Forests; D057232:Global Warming; D009656:North America; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D012621:Seasons; D013696:Temperature; D013997:Time Factors; D014197:Trees / Q000145:classification / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide