tailieunhanh - Báo cáo lâm nghiệp:"The d13C of Scots pine (Pinus sylvestris L.) needles: spatial and temporal variations"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"The d13C of Scots pine (Pinus sylvestris L.) needles: spatial and temporal variations" | Ann. For. Sci. 60 2003 97-104 97 INRA EDP Sciences 2003 DOI forest 2003001 Original article The 01 13C of Scots pine Pinus sylvestris L. needles spatial and temporal variations Oliver Brendel Linda Handley and Howard Griffiths Scottish Crop Research Institute Invergowrie Dundee DD2 5DA Scotland UK Received 10 January 2002 accepted 26 February 2002 Abstract - Spatial variation in carbon isotope composition S13C within the crown of an individual tree complicates sampling strategies but a systematic study has allowed constraining factors to be determined. Spatial and temporal variations of the S13C of Pinus sylvestris L. needles were investigated on three exposed south-facing branches over 17 months two growing seasons . A positive relationship about 2 0 m-1 was found between needle S13C and trunk-needle distance on the branch. Abaxial needles were characterized by less negative S13C values o compared with adaxial needles. Both effects were interpreted in terms of branch hydraulic conductivity including the presence of compression wood. A close relationship was found between S13C measured in needles and in adjoining branch wood. Correcting the monthly data for spatial variation a transient increase in needle S13C during spring was detected about o whereas changes in needle S13C during summer autumn and winter were minor and positively related to solar radiation. carbon isotope composition Pinus sylvestris needle branch length effect compression wood Résumé - Le S13C des aiguilles du Pin sylvestre Pinus sylvestris L. variations spatiales et temporelles. L existence d une variabilité en composition isotopique du carbone S13C dans la couronne d un arbre individuel complique les stratégies d échantillonnage. Il est nécessaire de déterminer les facteurs qui sont à l origine de cette variabilité. Les variations spatiales et temporelles de S13Caiguilles de Pinus sylvestris L. ont été étudiées pendant 17 mois deux périodes de végétation sur trois branches .