%0 Journal Article
%T Intra-seasonal dynamics in metabolic processes of 13C/12C and 18O/16O in components of Scots pine twigs from southern Siberia interpreted with a conceptual framework based on the Carbon Metabolism Oscillatory Model
%A Victor Voronin
%A Alexander A Ivlev
%A Vladimir Oskolkov
%A Tatjana Boettger
%J BMC Plant Biology
%D 2012
%I BioMed Central
%R 10.1186/1471-2229-12-76
%X The dynamics of carbon isotopic variables were studied in components of Pinus sylvestris L. in light and in dark chambers during the vegetation period from 14 June to 28 July 2006. At the beginning of this period water-soluble organic matter, mostly labile sugars (including sucrose as the main component) and newly formed bulk needle material, displayed relatively ¡°light¡± ¦Ä13C values (depletion in 13£¿C). Then, 13£¿C content increased again with noticeable ¡°depletion¡± events in the middle of the growth period. A gradual 13£¿C accumulation took place in the second half of the vegetation period. Similar effects were observed both in the light and in the dark with some temporal shifts. Environmental factors did not influence the ¦Ä13C values. A gradual 12C-depletion effect was noticed in needles of the previous year. The ¦Ä13C values of sucrose and proteins from needle biomass altered independently from each other in the light chamber. A distinct negative correlation between ¦Ä13C and ¦Ä18O values was revealed for all studied variables.The abrupt 13C depletion recorded by all tested trees for the period from June to July provides clear evidence of the transition from the dominant role of reserve carbohydrate pool (RCP) during the first half of the growth season to the preferable current year carbohydrate pool (CCP) consumption by new needles during its second half. The investigation of the isotopic signatures of Pinus sylvestris L. emphasizes the pivotal role of the intra-seasonal dynamics in carbon metabolism through the transport of assimilates from autotrophic (needles) to heterotrophic (twigs) organs of the studied trees. This provides an explanation for changes of carbon isotopic values observed within the growth season. The CMOM-based results support the hypothesis of the integration of three carbohydrate pools by photosynthesizing cells. The fluctuations of the carbon isotope ratios in different carbohydrate pools underlie various physiological processes in the tree met
%U http://www.biomedcentral.com/1471-2229/12/76