青藏高原高寒草地土壤中脂肪酸的分布特征

发布时间：2018-04-02 03:28

本文选题：青藏高原　切入点：土壤有机质　出处：《中国科学:地球科学》2016年06期

【摘要】：脂肪酸作为一种重要的生物标志物,已被广泛用于沉积物和土壤中有机质来源的示踪.青藏高原是世界上海拔最高的高原,也是亚洲许多大河沉积物的主要源.本研究在青藏高原高寒草地选择17个采样点,采集不同土层深度的土壤样品,通过测定土壤样品中总有机质参数和生物标志物脂肪酸的含量与组成,并结合环境要素(气温、降水和土壤理化性质)数据,阐明了青藏高原高寒草地不同土层深度脂肪酸的组成、来源和分布特征.结果表明:脂肪酸呈双峰型分布,以C_(16)和偶碳长链脂肪酸(C_(20)~C_(30))为主,表明土壤微生物和高等植物的混合输入源.源解析结果显示高等植物对青藏高原土壤中脂肪酸含量的贡献至少达40%.脂肪酸的含量随土层深度增加而降低,最大值为(1.08±0.09)mg/g OC(以OC计)出现在0~10cm层,最小值为(0.46±0.12)mg/g OC出现在50~70cm层,植物组织的输入在深层土壤中急剧减少是导致此现象的主要原因.与环境因子的相关性分析表明,脂肪酸总含量与年平均气温(P0.05)和土壤p H(P0.01)呈显著负相关关系,表明低温和低土壤p H更有益于青藏高原土壤中脂肪酸的保存.新鲜有机质来源的脂肪酸含量与年均降水呈显著正相关关系(P0.05),表明降水有助于新鲜有机质来源的脂肪酸在青藏高原土壤中的累积.此外,其他环境因素,如土壤矿物含量(铁、铝氧化物)、微生物群落组成、枯落物的质量和数量等,对青藏高原土壤中脂肪酸保留所起的作用亟待进一步研究,以便更好理解青藏高原高寒草地土壤中脂肪酸的保留机理.
[Abstract]:Fatty acids, as an important biomarker, have been widely used to trace the source of organic matter in sediments and soils. The Qinghai-Tibet Plateau is the highest altitude plateau in the world. In this study, 17 sampling sites were selected from alpine grasslands on the Qinghai-Tibet Plateau, and soil samples of different soil depths were collected. The content and composition of total organic matter parameters and biomarker fatty acids in soil samples were determined, and the data of environmental factors (temperature, precipitation and soil physical and chemical properties) were combined. The composition, source and distribution of fatty acids in different depths of alpine grassland in Qinghai-Xizang Plateau were described. The results showed that the fatty acids distributed in a bimodal pattern, with C _ (16) and C _ (20) C _ (20) C _ (20) C _ (P) C _ (30)). The results showed that the contribution of higher plants to the soil fatty acid content of Qinghai-Xizang Plateau was at least 40%, and the fatty acid content decreased with the increase of soil depth. The maximum value is 1.08 卤0.09)mg/g OC in 0~10cm layer and the minimum value is 0.46 卤0.12)mg/g OC in 50~70cm layer. The sharp decrease of plant tissue input in deep soil is the main cause of this phenomenon. The total fatty acid content was negatively correlated with the annual mean air temperature (P0.05) and soil pH (0.01). The results indicate that low temperature and low pH are more beneficial to the preservation of fatty acids in soil of Qinghai-Xizang Plateau. There is a significant positive correlation between the fatty acid content of fresh organic matter sources and annual precipitation (P 0.05), which indicates that precipitation contributes to the source of fresh organic matter. The accumulation of fatty acids in the soil of the Qinghai-Tibet Plateau. Other environmental factors, such as soil mineral content (iron, aluminum oxide, microbial community composition, quality and quantity of litter, etc.), need to be further studied on the role of fatty acid retention in soil of Qinghai-Xizang Plateau. In order to better understand the retention mechanism of fatty acids in alpine grassland soil of Qinghai-Tibet Plateau.
【作者单位】：中国科学院植物研究所植被与环境变化国家重点实验室;中国科学院西北高原生物研究所高原生物适应与进化重点实验室;北京大学城市与环境学院生态学系;
【基金】：国家重点基础研究发展计划项目(编号:2014CB954003,2015CB954201) 国家自然科学基金项目(批准号:31370491,41503073) 国家青年千人计划项目中国科学院战略性先导科技专项项目(编号:XDA05050404)资助
【分类号】：S812.2

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