Linked Life Data

17115189

Source:http://linkedlifedata.com/resource/pubmed/id/17115189

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-2-19
pubmed:abstractText
The stable C isotope composition (delta13C) of CO2 respired by trunks was examined in a mature temperate deciduous oak forest (Quercus petraea). Month-to-month, day-to-day and diurnal, measurements were made to determine the range of variations at different temporal scales. Trunk growth and respiration rates were assessed. Phloem tissue was sampled and was analysed for total organic matter and soluble sugar 13C composition. The CO2 respired by trunk was always enriched in 13C relative to the total organic matter, sometimes by as much as 5 per thousand. The delta13C of respired CO2 exhibited a large seasonal variation (3.3 per thousand), with a relative maximum at the beginning of the growth period. The lowest values occurred in summer when the respiration rates were maximal. After the cessation of radial trunk growth, the respired CO2 delta13C values showed a progressive increase, which was linked to a parallel increase in soluble sugar content in the phloem tissue (R=0.95; P<0.01). At the same time, the respiration rates declined. This limited use of the substrate pool might allow the discrimination during respiration to be more strongly expressed. The late-season increase in CO2 delta13C might also be linked to a shift from recently assimilated C to reserves. At the seasonal scale, CO2 delta13C was negatively correlated with air temperature (R=-0.80; P<0.01). The diurnal variation sometimes reached 3 per thousand, but the range and the pattern depended on the period within the growing season. Contrary to expectations, diurnal variations were maximal in winter and spring when the leaves were missing or not totally functional. By contrast to the seasonal scale, these diurnal variations were not related to air temperature or sugar content. Our study shows that seasonal and diurnal variations of respired 13C exhibited a similar large range but were probably explained by different mechanisms.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0029-8549
pubmed:author
pubmed:issnType
Print
pubmed:volume
151
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
268-79
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Seasonal, daily and diurnal variations in the stable carbon isotope composition of carbon dioxide respired by tree trunks in a deciduous oak forest.
pubmed:affiliation
Laboratoire d'Ecologie, Systématique et Evolution (ESE), Université Paris XI, CNRS UMR 8079, Bâtiment 362, 91405, Orsay Cedex, France. florence.maunoury@ese.u-psud.fr
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't