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Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: N 15 partitioning and production of 15 N-labelled litter in beech trees. | Ann. Sci. For. 55 1998 375-383 Inra Elsevier Paris 375 Original article 15N partitioning and production of 15N-labelled litter in beech trees following 15N urea spray Bernd Zeller Micheline Colin-Belgrand Etienne Dambrine Francis Martin Écosystèmes forestiers Centre Inra Nancy 54280 Champenoux France Received 16 June 1997 accepted 12 November 1997 Abstract - The leaves of 10-year-old beech trees grown in a plantation were sprayed once in late summer in 1993 1994 and 1995 with l5N urea to determine the l5N utilization by beech Fagus sylvatica L. and to obtain homogeneous l5N-labelled litter. One day after spraying leaves had incorporated 42 1993 to 55 1995 of the applied 15N urea. The leaf amino acid content and N concentration increased shortly after application. During leaf senescence approximately 88 of the incorporated 15N was translocated and mainly stored in the above-ground biomass. After spraying N concentration and l5N enrichment of leaves were measured until abscission. In spring trees were sampled and l5N allocation in above- and below-ground organs were determined to assess l5N partitioning. Buds and bark showed the highest 15N enrichment but the largest amounts of foliarly applied l5N were stored in bark and wood. I5N enrichment of fallen leaves i.e. litter increased after each l5N urea spray from 2.11 l5N atom excess in 1993 to 2.97 5N in 1994 and 3.14 l5N in 1995. Annual litter contained 4.7 7.3 and 7.8 of the sprayed l5N. Soluble and insoluble N fractions showed an identical l5N atom excess indicating a homogeneous distribution of l5N in the labelled leaves as well as litter. Inra Elsevier Paris. 15N urea beech litter forest nitrogen Resume - Repartition de 1SN dans le hêtre et production d une litière marquee après pulverisation de l5N urée. Afin de determiner utilisation de 1 azote par le hêtre Fagus sylvaúca L. et pour obtenir une litière homogène marquee au l5N de Turée enrichie en l5N a été pulvé-risée en fin d été 1993. 1994 et 1995 sur le .
