title: Consistent leaf respiratory response to experimental warming of three North American deciduous trees: a comparison across seasons, years, habitats and sites.
abstract: Most vascular plants acclimate respiration to changes in ambient temperature, but explicit tests of these responses in field settings are rare, and how acclimation responses vary in space and time is relatively unstudied, hindering our ability to predict respiratory release of carbon under future climatic conditions. We measured temperature response curves of leaf respiration for three deciduous tree species from 2009 to 2012 in a field warming experiment (+3.4 °C above ambient) in both open and understory conditions at two sites in the southern boreal forest in Minnesota, USA. We analyzed the effects of warming on leaf respiration, and how the effects varied among species, times of season (early, middle and late parts of the growing season), sites, habitats (understory, open) and years. We hypothesized that the respiration exponent (Q10) of the short-term temperature response curve and the degree of acclimation would be smaller under conditions where plants were more likely to be substrate limited, such as in the understory or the margins of the growing season. However, in contrast to these predictions, stable Q10 and strong respiratory acclimation were consistently observed. For each species, the Q10 did not vary with experimental warming, nor was its response to warming influenced by time of season, year, site or habitat. Strong leaf respiratory acclimation to warming occurred in each species and was consistent across most sources of variation. Most of the leaf traits studied were not affected by warming, while the Q10-leaf nitrogen and R25-soluble carbohydrate relationships were observed, and shifted with warming, implying that acclimation may be associated with the adjustment in respiratory capacity and its relation to leaf nitrogen and soluble carbohydrate content. Consistent Q10 and acclimation across habitats, sites, times of season and years suggest that modeling of temperature acclimation may be possible with relatively simple functions.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Xinong Road 26, Yangling 712100, China.|Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.
authors.forename: Kerrie M
authors.initials: KM
authors.lastname: Sendall
authors.affiliation: Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.
authors.forename: Artur
authors.initials: A
authors.lastname: Stefanski
authors.affiliation: State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, South Tianshui Road 222, Lanzhou University, Lanzhou 730000, China.
authors.forename: Changming
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, East Qinghua Road 35, Beijing 100083, China.
authors.forename: Jihua
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.
authors.forename: Roy L
authors.initials: RL
authors.lastname: Rich
authors.affiliation: Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Montgomery
authors.affiliation: Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue N, St Paul, MN 55108, USA.|Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW 2753, Australia.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Reich
mesh_terms: D000064:Acclimatization; D017753:Ecosystem; D018515:Plant Leaves / Q000502:physiology*; D018526:Plant Transpiration; D012621:Seasons; D013696:Temperature; D014197:Trees / Q000502:physiology*; D014481:United States
keywords: Q10; effect size; experimental warming; leaf traits; respiration–temperature response curves; respiratory acclimation