tailieunhanh - Báo cáo lâm nghiệp:"Inter-annual mobility of nitrogen between beech rings: a labelling experiment"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"Inter-annual mobility of nitrogen between beech rings: a labelling experiment" | Ann. For. Sci. 60 2003 503-508 INRA EDP Sciences 2003 DOI forest 2003043 503 Original article Inter-annual mobility of nitrogen between beech rings a labelling experiment Sliman ELHANIa Brígida Fernández LEMAa b Bernd ZELLERc Claude BRÉCHETa Jean-Marc GUEHLa Jean-Luc DUPOUEYa a UMR-Écologie et Écophysiologie Forestières INRA-Nancy 54280 Champenoux France b Present address Área de Ecoloxía Facultade de Bioloxía Universidade de Santiago de Compostela 15782 Santiago de Compostela Spain c Biogéochimie des Ecosystèmes Forestiers INRA-Nancy 54280 Champenoux France Received 23 October 2002 accepted 25 March 2003 Abstract - Nitrogen concentration N and isotopic composition S15N in annual growth rings of 16-year-old beech trees Fagus sylvatica L. were measured before and after treatment of wood using organic solvents. The trees grown under field conditions in Northeastern France were labelled with 15N-enriched urea solution at leaf level for three successive years 1993 1994 and 1995 and were sampled in 2001. S15N values in this experiment ranged from -4 to -7 0 for non-labelled tree. Labelling resulted in markedly increased S15N of whole wood for years 1994 1995 and 1996. Significant labelling-induced increases compared to non-labelled rings in S15N were also found in the rings formed before and after the labelling period pointing to an important mobility of N across the rings. The extraction removed 36 of total nitrogen and 14 of total carbon. The treatment improved the inter-annual resolution of N and S15N but did not reduce the 15N signal in rings prior to labelling to the same level as in control tree as was expected. After extraction significant correlation between August precipitation and N variations at the inter-annual level was found for the 1990-2000 period. nitrogen 15 isotopic labelling internal transfer tree ring Fagus sylvatica Résumé - Mobilité de l azote dans les cernes annuels de hêtre une experience de marquage. La concentration N et la composition