【作者】 董红云；

【导师】 孔垂华；

【作者基本信息】 中国农业大学 ， 生态学， 2014， 博士

【摘要】 沉积物中木栓酮作为指示被子植物的生物标记物,可追溯地球古环境和古植被的历史变化。本研究对土壤木栓酮的来源、积累途径和稳定性,以及对土壤微生物群落组成和结构的影响进行分析,并选取全国34个典型森林和农田生态系统样点进行研究,探索土壤木栓酮的分布特征,以及土壤木栓酮在森林和农田生态系统的生态指示作用。研究结果显示,木栓酮在我国不同植被区常见植物中普遍存在,并具有种属特异性。主要经由凋落物途径进入土壤,在土壤中较稳定,半衰期t1/2=54d (K=0.013,Y=0.218+4.62e-0.013t,r2=0.993)。木栓酮对土壤活性有显著影响,通过平板计数法和磷脂脂肪酸法发现木栓酮对土壤微生物群落组成和结构均有显著影响。木栓酮在土壤中的垂直分布规律表现为表层土壤显著高于其他深度土壤,深层土壤(20-100cm)木栓酮含量没有显著变化。士壤木栓酮随季节波动,但在较长时间尺度下维持稳定。术栓酮在森林和农田生态系统土壤中广泛存在(0.02-6.27μg/g土),森林土壤木栓酮含量普遍大于农田,自然生态系统土壤普遍大于人工生态系统(天然林>人工林,撂荒地>农田)。土壤木栓酮的空间分布规律是受土地利用方式、气候因子和土壤因子等多种环境因子共同作用的结果。土地利用方式对土壤木栓酮有显著影响,气候因子对土壤木栓酮有显著间接影响。土壤木栓酮与土壤有机质、土壤pH值极显著相关,土壤pH对土壤木栓酮的影响效应大于土壤有机质。木栓酮在森林生态系统土壤中普遍存在(0.17-6.27μg/g土),不同林型间存在显著差异。天然林土壤中木栓酮含量远高于人工林,人工针叶林和人工阔叶林不因叶差异而存在差异,人工针阔混交林土壤中木栓酮含量小于人工针叶林和人工阔叶林。随着植物群落的演替,表层土壤中木栓酮含量逐渐升高。木栓酮在农田生态系统土壤中普遍存在(0.02-0.32μg/g土),不同土地利用方式表层土壤间存在显著差异,撂荒地和农田防护林土壤中木栓酮含量显著大于农田,水田和旱田没有明显差异。在不同耕作模式下,长期施肥土壤中木栓酮含量最低。分析森林和农田土壤木栓酮与土壤理化性质和土壤微生物群落组成和结构的相关性,较小空间尺度下土壤木栓酮仅与土壤真菌菌群存在显著相关性,森林土壤与土壤全N显著相关,而农田土壤有机质和土壤微生物量碳显著相关。综合分析森林和农田生态系统土壤木栓酮与植被、空间位置、气候因子、土壤因子以及土地利用方式等环境因子的关联性,发现土壤中木栓酮对人为干扰具有生态指示作用,建议土壤中木栓酮可作为生物标志物对生态系统脆弱度和恢复程度作出有效评估。更多还原

【Abstract】 Friedelin as a lipid biomarker of angiosperms in sediments has been used to reconstruct the change of the ancient vagatation and environment. To explore the role of ecological indicators of soil friedelin in the agricultural and forest ecosystem, the source, accumulate ways, stability and the impact on soil microbial community composition and structure of soil fridedlin were analyzed respectively. Thiry-four typical agricultural and forest ecosystem sites were seleted to investigate broad-scale patterns and ecological significance of soil friedelin.Dominant plants in various vegetation zones of China contain fridelin prevalently with species specificity. It keeps stable with half life period t1/2=54d (K=0.013, Y=0.218+4.62e-0013t, r2=0.993) after the soil fridedlin inputs from plants via litter. Friedelin has significant impact on soil activity, microbial community composition and structure analyzed by plate count and phospholipid fatty acids method. Friedlin of topsoil is significant higher than that of other soil depth, no significant change with increasing depth. Soil friedelin remains stable over years scale, even though it shows seasonal fluctuation.Friedelin is widespread in soil of forest and agricultural ecosystems (0.02-6.27μg/g soil). The content of forest ecosystem is commen higher than that of agroecosystem. Soil friedelin in natural ecosystem is generally greater than artificial ecosystem (natural forest> plantation, fallowland> farmland). The geographic pattern is shaped by a variety of environmental factors of land use, climatic and soil. Land use change induced by human influences has a significant impact on soil friedelin, however climatic factors have a strong indirect impact on soil friedelin. Soil friedelin correlates significantly with both soil organic matter and soil pH, with soil pH showing a stronger influence on soil friedelin than SOM.Friedelin is prevalent in soil of forest ecosystem (0.17-6.27/μg/g soil). There are significant difference between various forest types. Soil friedelin in natural forest is much higher than plantations, of which coniferous and broadleaf plantations have no significant difference in spite of leaf type, and their soil friedelin content higher than coniferous and broadleaf mixed plantations. The content of topsoil friedelin increased with the succession of plant communities. Friedelin is prevalent in agroecosystem (0.02-0.32μg/g soil). There are significant difference between various Land uses. Soil friedelin in abandoned land and farmland shelterbelts are much higher than that in farmland, of which paddy and maize field have no obvious difference. Long-term fertilization has minimum friedelin content among various tillages. Correlation analysis were calculated between soil friedelin and soil properties, and soil microbial community. Soil friedelin significantly correlated with soil fungi PLFA of forest and farmland, soil organic matter and soil microbial biomass of agroecosystem merely, and assosicated with forest soil biotic facters slightly, exclusive of soil total N. Correlation analysis were calculated among soil friedelin and vegetation, spatial location, land use, climatic and soil factors comprehensively. The results suggest that soil friedelin is a useful biomarker indicating anthropogenic interference, that can be used to effectively assess the vulnerability and recovery of ecosystem.更多还原