title: Elevation of night-time temperature increases terpenoid emissions from Betula pendula and Populus tremula.
abstract: Volatile organic compounds (VOCs) are expected to have an important role in plant adaptation to high temperatures. The impacts of increasing night-time temperature on daytime terpenoid emissions and related gene expression in silver birch (Betula pendula) and European aspen (Populus tremula) clones were studied. The plants were grown under five different night-time temperatures (6, 10, 14, 18, and 22 degrees C) while daytime temperature was kept at a constant 22 degrees C. VOC emissions were collected during the daytime and analysed by gas chromatography-mass spectrometry (GC-MS). In birch, emissions per leaf area of the C11 homoterpene 4,8-dimethy1-nona-1,3,7-triene (DMNT) and several sesquiterpenes were consistently increased with increasing night-time temperature. Total sesquiterpene (SQT) emissions showed an increase at higher temperatures. In aspen, emissions of DMNT and beta-ocimene increased from 6 degrees C to 14 degrees C, while several other monoterpenes and the SQTs (Z,E)-alpha-farnesene and (E,E)-alpha-farnesene increased up to 18 degrees C. Total monoterpene and sesquiterpene emission peaked at 18 degrees C, whereas isoprene emissions decreased at 22 degrees C. Leaf area increased across the temperature range of 6-22 degrees C by 32% in birch and by 59% in aspen. Specific leaf area (SLA) was also increased in both species. The genetic regulation of VOC emissions seems to be very complex, as indicated by several inverse relationships between emission profiles and expression of several regulatory genes (DXR, DXS, and IPP). The study indicates that increasing night temperature may strongly affect the quantity and quality of daytime VOC emissions of northern deciduous trees.
authors.affiliation: Department of Environmental Science, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland. Mohamed.Ibrahim@uef.fi
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Ibrahim
authors.forename: Maarit
authors.initials: M
authors.lastname: Mäenpää
authors.forename: Viivi
authors.initials: V
authors.lastname: Hassinen
authors.forename: Sari
authors.initials: S
authors.lastname: Kontunen-Soppela
authors.forename: Lukás
authors.initials: L
authors.lastname: Malec
authors.forename: Matti
authors.initials: M
authors.lastname: Rousi
authors.forename: Liisa
authors.initials: L
authors.lastname: Pietikäinen
authors.forename: Arja
authors.initials: A
authors.lastname: Tervahauta
authors.forename: Sirpa
authors.initials: S
authors.lastname: Kärenlampi
authors.forename: Jarmo K
authors.initials: JK
authors.lastname: Holopainen
authors.forename: Elina J
authors.initials: EJ
authors.lastname: Oksanen
mesh_terms: D000475:Alkenes / Q000378:metabolism; D029662:Betula / Q000235:genetics / Q000378:metabolism*; D002070:Butadienes / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D045782:Hemiterpenes / Q000378:metabolism; D039821:Monoterpenes / Q000378:metabolism; D010420:Pentanes / Q000378:metabolism; D016133:Polymerase Chain Reaction; D032107:Populus / Q000235:genetics / Q000378:metabolism*; D012717:Sesquiterpenes / Q000378:metabolism; D013696:Temperature; D013729:Terpenes / Q000378:metabolism*; D055549:Volatile Organic Compounds / Q000378:metabolism; D014835:Volatilization
chemical_list: C411254:4,8-dimethyl-1,3,7-nonatriene; D000475:Alkenes; D002070:Butadienes; D045782:Hemiterpenes; D039821:Monoterpenes; D010420:Pentanes; D012717:Sesquiterpenes; D013729:Terpenes; D055549:Volatile Organic Compounds; C005059:isoprene; C062672:alpha-farnesene