中文摘要：

根据大九湖泥炭柱样的木质素特征，结合C／N、δ13C和δ15N数据，分析了有机物的来源和降解特征。结果表明，陆地C3高等植物是有机物的主要来源。木质素的S／V和C／V参数指示该泥沼的主要维管植物是草本被子植物。有机碳含量（OC）的变化与这些植被参数具有良好的对应关系，说明植被变化是控制有机碳含量的重要因素。（Ad／Al）v和（Ad／Al）s参数表明泥炭中的木质素经历了中等程度的氧化降解，而棕腐菌的去甲基／去甲氧基过程是控制木质素含量的主要降解途径。木质素在埋藏后的降解很小，其降解程度更多地受对应年代的环境条件的控制，例如，在温暖湿润的全新世气候最适宜期，木质素降解程度显著高于之前的寒冷干燥时期。

英文摘要：

Lignin characteristics of a peat core collected from Lake Dajiu were studied to investigate the sources of organic matter and degradation states. For the entire core, the average content of organic carbon （OC） was 43.4%; ratios of C/N, δ13C and δ15N （averaged at 28.5, -27.5%0 and 0. 8‰ respectively） indicated that terrestrial C3 vegetation was the main source of the organic matter. Ratios of S/V and C/V （averaged at 1.4 ± 0.3 and 0.9±0. 2, respectively） suggested that nonwoody angiosperms were the dominant vascular plants. The variation of OC corresponded with those parameters, which suggested vegetation plays an important role on OC. （Ad/Al）v and （Ad/Al）s were 0.43 ±0.09 and 0. 36±0.06, respectively, indicating moderate oxidation degradation states of lignin. Good correlations were observed for A8 vs. P/（V＋S） and DHBA/V, thus demethylation/demethoxylation should be the main decomposition pathway. The degradation processes of lignin after burial were minor, thus these degradation indicators probably kept the in geological times. For example, higher microbial alterations during warm and wet indicated than those in cool and dry periods. situ environmental information in Holocene Climate Optimum were