Department of Plant, Soil, and Environmental Sciences, University of Maine, Orono, Maine 04469-5722, USA.
Environ Sci Technol. 2010 Nov 15;44(22):8594-8600. doi: 10.1021/es101089t.
The chemical properties of organic matter affect important soil processes such as speciation, solubilization, and transport of plant nutrients and metals. This work uses ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to determine the molecular composition of three organic matter fractions of soils and aqueous extracts of crop biomass. Comparison of the van Krevelen plots allowed tracking the changes in organic matter with increasing humification. Aqueous plant biomass extracts contain a diverse mixture of lipids, proteins, and lignins. Soil aqueous extracts were marked by increases in lignin and carbohydrate components and decrease in the protein component as compared to the plant extract. Refractory humic acid fractions were marked by decrease in the lignin component and increases in the lipid and condensed aromatic components. The multivariate indicator species analysis was used to identify marker components of the four organic matter types investigated. The plant extract group had 772 marker components compared to 237 for soil aqueous extract, 92 for mobile humic acid, and 418 for calcium humic acid. This study demonstrates that ultrahigh resolution mass spectrometry and multivariate methods can be used to identify marker components to gain a molecular-scale description and understanding of C dynamics.
有机物的化学性质会影响到一些重要的土壤过程，如植物养分和金属的形态、溶解和迁移。本研究采用超高效分辨率电喷雾电离傅里叶变换离子回旋共振质谱法，对土壤和作物生物质水提物中的三种有机物组分进行了分子组成的测定。通过范特霍夫图谱的对比，可以追踪有机物随腐殖化程度增加而发生的变化。水提植物生物质中含有多种脂质、蛋白质和木质素。与植物提取物相比，土壤水提取物中木质素和碳水化合物的含量增加，而蛋白质的含量则降低。难溶性腐殖酸中木质素的含量降低，而脂质和缩合芳烃的含量增加。多变量指示种分析用于鉴定所研究的四种有机物类型的标记成分。与土壤水提取物（237 种）、移动腐殖酸（92 种）和钙腐殖酸（418 种）相比，植物提取物组有 772 种标记成分。本研究表明，超高分辨率质谱和多变量方法可用于鉴定标记成分，从而在分子尺度上对 C 动态进行描述和理解。
