目的探索稳定同位素碳氮对大枣产地溯源的可行性。方法用同位素比质谱仪(isotopic ratio mass spectrometry,IMRS)测定河北省赞皇、行唐、阜平3县10个枣园的大枣果肉中的δ~13C和δ~15N值,通过聚类分析,研究太行山中麓大枣枣肉中同位素...目的探索稳定同位素碳氮对大枣产地溯源的可行性。方法用同位素比质谱仪(isotopic ratio mass spectrometry,IMRS)测定河北省赞皇、行唐、阜平3县10个枣园的大枣果肉中的δ~13C和δ~15N值,通过聚类分析,研究太行山中麓大枣枣肉中同位素组成的区域分布。结果阜平县不施肥组c3自成一类,赞皇县50%样品聚为第二类,行唐100%样品聚为第三类,赞皇和阜平剩余样品与行唐样品存在交叉。结论赞皇、行唐、阜平三地大枣枣肉中C、N同位素组成存在差异,用同位素技术对大枣进行产地溯源是可行的。展开更多
This study dealt with the distribution characteristics of soil organic carbon (SOC) and the variation of stable carbon isotopic composition (δ13C values) with depth in six soil profiles, including two soil types and ...This study dealt with the distribution characteristics of soil organic carbon (SOC) and the variation of stable carbon isotopic composition (δ13C values) with depth in six soil profiles, including two soil types and three vegetation forms in the karst areas of Southwest China. The δ13C values of plant-dominant species, leaf litter and soils were measured using the sealed-tube high-temperature combustion method. Soil organic carbon contents of the limestone soil profiles are all above 11.4 g/kg, with the highest value of 71.1 g/kg in the surface soil. However, the contents vary between 2.9 g/kg and 46.0 g/kg in three yellow soil profiles. The difference between the maximum and minimum δ13C values of soil organic matter (SOM) changes from 2.2‰ to 2.9‰ for the three yellow soil profiles. But it changes from 0.8‰ to 1.6‰ for the limestone soil profiles. The contrast research indicated that there existed significant difference in vertical patterns of organic carbon and δ13C values of SOM between yellow soil and limestone soil. This difference may reflect site-specific factors, such as soil type, vegetation form, soil pH value, and clay content, etc., which control the contents of different organic components comprising SOM and soil carbon turnover rates in the profiles. The vertical variation patterns of stable carbon isotope in SOM have a distinct regional character in the karst areas.展开更多
文摘目的探索稳定同位素碳氮对大枣产地溯源的可行性。方法用同位素比质谱仪(isotopic ratio mass spectrometry,IMRS)测定河北省赞皇、行唐、阜平3县10个枣园的大枣果肉中的δ~13C和δ~15N值,通过聚类分析,研究太行山中麓大枣枣肉中同位素组成的区域分布。结果阜平县不施肥组c3自成一类,赞皇县50%样品聚为第二类,行唐100%样品聚为第三类,赞皇和阜平剩余样品与行唐样品存在交叉。结论赞皇、行唐、阜平三地大枣枣肉中C、N同位素组成存在差异,用同位素技术对大枣进行产地溯源是可行的。
文摘对长汀水土流失区不同生态恢复程度生境马尾松(Pinus massoniana)与木荷(Schima superba)的叶片稳定碳同位素组成(δ13C)、比叶面积(specific leaf area,SLA)、叶N含量及C/N进行了分析,并以叶片δ13C值和C/N分别指示植物的水分利用效率(water use efficiency,WUE)和氮素利用效率(nitrogen use efficiency,NUE).研究发现:1)随着生境恢复程度的提高,马尾松与木荷的δ13C值均呈下降趋势,其中木荷对环境的响应比马尾松敏感.2)同一生境,马尾松的δ13C值高于木荷,植被恢复程度较高的生境两者差异更明显,δ13C值变幅为2.20‰.3)相同生境,马尾松的NUE高于木荷,SLA和叶N含量低于木荷,恢复程度较高的生境差异显著(P<0.05).4)树种间的NUE与WUE不存在权衡,SLA和叶N含量的变化趋势与WUE相反.研究结果表明:马尾松与木荷WUE对资源梯度变化的响应趋势相似,木荷的可塑性较强;在干旱贫瘠生境中,马尾松比木荷具有更保守的水分利用方式和氮素消费方式,适应能力更强,能起先锋树种作用,随着生态恢复程度的提高,木荷具有更强的资源竞争能力和生态适应性.
文摘This study dealt with the distribution characteristics of soil organic carbon (SOC) and the variation of stable carbon isotopic composition (δ13C values) with depth in six soil profiles, including two soil types and three vegetation forms in the karst areas of Southwest China. The δ13C values of plant-dominant species, leaf litter and soils were measured using the sealed-tube high-temperature combustion method. Soil organic carbon contents of the limestone soil profiles are all above 11.4 g/kg, with the highest value of 71.1 g/kg in the surface soil. However, the contents vary between 2.9 g/kg and 46.0 g/kg in three yellow soil profiles. The difference between the maximum and minimum δ13C values of soil organic matter (SOM) changes from 2.2‰ to 2.9‰ for the three yellow soil profiles. But it changes from 0.8‰ to 1.6‰ for the limestone soil profiles. The contrast research indicated that there existed significant difference in vertical patterns of organic carbon and δ13C values of SOM between yellow soil and limestone soil. This difference may reflect site-specific factors, such as soil type, vegetation form, soil pH value, and clay content, etc., which control the contents of different organic components comprising SOM and soil carbon turnover rates in the profiles. The vertical variation patterns of stable carbon isotope in SOM have a distinct regional character in the karst areas.
