Abstract

Proportions of ¹³C/¹²C and ¹⁵N/¹⁴N isotopes were identified in different woody compartments of birch (Betula pendula Roth), pine (Pinus sylvestris L.) and aspen (Populus tremula L.) trunks in preforest-steppe and pine-birch forests of the Middle Urals using mass spectrometry. The data were analyzed and interpreted from the perspective of the biochemical processes of carbon and nitrogen metabolism in leaves, cambial tissue, trunk wood, branches, roots, and soil. A lighter isotopic composition of carbon is characteristic of the leaves and trunk cambium. The trunk wood is characterized by a basal trend for ¹³C enrichment. The ¹³C/¹²C ratio corresponds to the nitrogen content in the trunk wood tissues, indicating metabolic control of carbon fractionation in woody plants. The isotope composition of nitrogen in the trunk cambium was significantly depleted in ¹⁵N (δ¹⁵N varies from –1.5 to –3.5‰) and δ¹³C (δ¹³C varies from –28.3 to –25.8‰). Meanwhile the sapwood (δ¹⁵N varies from –2.6 to 1‰ and δ¹³C varies from –27.5 to –27.1‰) and heartwood (δ¹⁵N varies from –2.5 to –3.5‰ and δ¹³C varies from –26 to –24.5‰) were more enriched in ¹⁵N and ¹³C. The significant difference between the values of ¹³C and ¹⁵N isotope discrimination consequently in the different woody compartments of trunk should be taken into account when interpreting data of wood organic matter in the context of paleoclimate.

中文翻译：

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樟子松，桦和et的木材的碳和氮同位素组成

摘要

在森林前草原和松树的桦木（Betula pendula Roth），松木（Pinus sylvestris L.）和白杨木（Populus tremula L.）的不同木质区室中鉴定出¹³ C / ¹² C和¹⁵ N / ¹⁴ N同位素的比例。质谱法测定中乌拉尔的白桦林。从叶子，冈比亚组织，树干木材，树枝，根和土壤中碳和氮代谢的生化过程的角度对数据进行了分析和解释。碳和碳的同位素组成较轻，是叶片和树干形成层的特征。树干木材的基本趋势是¹³ C富集。的¹³ C / ¹² C之比对应于行李箱木组织的氮含量，这表明木本植物碳分馏的代谢控制。氮在躯干形成层的同位素组成在被显著耗尽¹⁵ N（δ ¹⁵ ñ变化从-1.5至-3.5‰）和δ ¹³ C（δ ¹³ C ^变化从-28.3至-25.8‰）。同时，边材（δ ¹⁵ ñ变化从-2.6至1‰和δ ¹³ Ç变化从-27.5至-27.1‰）和心材（δ ¹⁵ ñ变化从-2.5到-3.5‰和δ ¹³ C来自-26变化到–24.5‰）富含¹⁵ N和¹³C.因此，在古气候背景下解释木材有机物数据时，应考虑到树干不同木质区室中¹³ C和¹⁵ N同位素判别值之间的显着差异。