title: Interactions between temperature and intercellular CO2concentration in controlling leaf isoprene emission rates.
abstract: Plant isoprene emissions have been linked to several reaction pathways involved in atmospheric photochemistry. Evidence exists from a limited set of past observations that isoprene emission rate (Is) decreases as a function of increasing atmospheric CO2concentration, and that increased temperature suppresses the CO2effect. We studied interactions between intercellular CO2concentration (Ci) and temperature as they affect Isin field-grown hybrid poplar trees in one of the warmest climates on earth - the Sonoran Desert of the southwestern United States. We observed an unexpected midsummer downregulation of Isdespite the persistence of relatively high temperatures. High temperature suppression of the Is:Cirelation occurred at all times during the growing season, but sensitivity of Isto increased Ciwas greatest during the midsummer period when Iswas lowest. We interpret the seasonal downregulation of Isand increased sensitivity of Isto Cias being caused by weather changes associated with the onset of a regional monsoon system. Our observations on the temperature suppression of the Is:Cirelation are best explained by the existence of a small pool of chloroplastic inorganic phosphate, balanced by several large, connected metabolic fluxes, which together, determine the Ciand temperature dependencies of phosphoenolpyruvate import into the chloroplast.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA. russmonson@email.arizona.edu.|Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, 85721, USA. russmonson@email.arizona.edu.
authors.forename: Russell K
authors.initials: RK
authors.lastname: Monson
authors.affiliation: Department of Biology, Hiram College, Hiram, Ohio, 44234, USA.
authors.forename: Amberly A
authors.initials: AA
authors.lastname: Neice
authors.affiliation: School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Trahan
authors.affiliation: School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Shiach
authors.affiliation: Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA.
authors.forename: Joel T
authors.initials: JT
authors.lastname: McCorkel
authors.affiliation: School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA.
authors.forename: David J P
authors.initials: DJ
authors.lastname: Moore
mesh_terms: D002070:Butadienes / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D018869:Heat-Shock Response; D045782:Hemiterpenes / Q000378:metabolism*; D010420:Pentanes / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D032107:Populus / Q000378:metabolism*; D013696:Temperature
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D002245:Carbon Dioxide
keywords: abiotic; hot; model; ozone; photosynthesis; stress; terpene; thermotolerance