title: The relationship between needle sugar carbon isotope ratios and tree rings of larch in Siberia.
abstract: Significant gaps still exist in our knowledge about post-photosynthetic leaf level and downstream metabolic processes and isotopic fractionations. This includes their impact on the isotopic climate signal stored in the carbon isotope composition (δ(13)C) of leaf assimilates and tree rings. For the first time, we compared the seasonal δ(13)C variability of leaf sucrose with intra-annual, high-resolution δ(13)C signature of tree rings from larch (Larix gmelinii Rupr.). The trees were growing at two sites in the continuous permafrost zone of Siberia with different growth conditions. Our results indicate very similar low-frequency intra-seasonal trends of the sucrose and tree ring δ(13)C records with little or no indication for the use of 'old' photosynthates formed during the previous year(s). The comparison of leaf sucrose δ(13)C values with that in other leaf sugars and in tree rings elucidates the cause for the reported (13)C-enrichment of sink organs compared with leaves. We observed that while the average δ(13)C of all needle sugars was 1.2‰ more negative than δ(13)C value of wood, the δ(13)C value of the transport sugar sucrose was on an average 1.0‰ more positive than that of wood. Our study shows a high potential of the combined use of compound-specific isotope analysis of sugars (leaf and phloem) with intra-annual tree ring δ(13)C measurements for deepening our understanding about the mechanisms controlling the isotope variability in tree rings under different environmental conditions.
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland Present address: Natural Resources Institute Finland, PO Box 18, FI-01301 Vantaa, Finland katja.rinne-garmston@luke.fi.
authors.forename: K T
authors.initials: KT
authors.lastname: Rinne
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Saurer
authors.affiliation: V.N. Sukachev Institute of Forest SB RAS, Akademgorodok, Krasnoyarsk 660036, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Kirdyanov
authors.affiliation: Department of Geography, Swansea University, Singleton Park, Swansea SA2 8PP, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Loader
authors.affiliation: V.N. Sukachev Institute of Forest SB RAS, Akademgorodok, Krasnoyarsk 660036, Russia.
authors.forename: M V
authors.initials: MV
authors.lastname: Bryukhanova
authors.affiliation: Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland.
authors.forename: R A
authors.initials: RA
authors.lastname: Werner
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland.
authors.forename: R T W
authors.initials: RT
authors.lastname: Siegwolf
mesh_terms: D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D002247:Carbon Isotopes; D028221:Larix / Q000254:growth & development* / Q000378:metabolism*; D063245:Plant Development / Q000502:physiology*; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D002247:Carbon Isotopes; D002244:Carbon
keywords: Central Siberia; Larix gmelinii (Rupr.); carbohydrates; climate; compound-specific; laser ablation; post-photosynthetic; sucrose