Characterisation of soil organic phosphorus in NaOH-EDTA extracts: A comparison of 31P NMR spectroscopy and enzyme addition assays
Characterisation of soil organic phosphorus in NaOH-EDTA extracts: A comparison of 31P NMR spectroscopy and enzyme addition assays
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DOI：
10.1016/j.soilbio.2015.09.010
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发表时间：
2015-12-01
影响因子：
9.7
通讯作者：
Buenemann, Else K.
中科院分区：
文献类型：
--
作者：
Jarosch, Klaus A.;Doolette, Ashlea L.;Buenemann, Else K.
不同土壤有机磷化合物的识别和定量对于更好地了解土壤磷动态至关重要。本研究的目的是比较两种常用的表征方法：P-31 NMR光谱法和酶添加试验（EAA）。同样的0.25 M NaOH和0.05 M乙二胺四乙酸（EDTA）提取物的10个温带和热带表土下耕地作物或永久性草地进行了分析，通过每种方法。此外，通过对一种酶处理的土壤提取物的P-31 NMR分析来验证所用酶的底物特异性。最后，有机磷的分子量分布，其特征在于使用凝胶过滤色谱。NaOH-EDTA可提取的有机磷含量为7 ~ 1108 mg·kg ~（-1）。使用P-31 NMR光谱，六个有机P物种在单和二酯区加上正磷酸盐，焦磷酸盐和膦酸盐进行了检测。由于信噪比差，两种土壤的P-31 NMR谱不可能进行反卷积。使用EAAs，肌醇磷酸类P被确定为最大的酶不稳定的有机磷类在大多数土壤中，其次是单酯类P和DNA类P。相应的类P-31 NMR和EAAs确定的有机磷的建立和浓度被发现同意一般。然而，P-31 NMR光谱的可重复性高于EAA。酶处理的提取物的P-31 NMR光谱表明，每种酶作用于预期的有机P类，虽然用植酸酶处理引起了一个新的，但未识别的峰在单酯区域的外观。碱性提取物的凝胶过滤色谱显示存在高分子量有机P（>5 kDa），其与酶稳定P具有1：1的关系。对于这两种方法，相对于所需的样品预处理，分析时间和成本以及可识别化合物的总数的优点和缺点进行了讨论。虽然EAA适用于快速和粗略的表征较大的样品数量，P-31 NMR是更强大的，并允许更详细的定量磷的形式。(C)2015爱思唯尔有限公司版权所有。
The identification and quantification of different soil organic phosphorus (P) compounds is crucial for a better understanding of soil P dynamics. The aim of this study was to compare two commonly used characterisation methods: P-31 NMR spectroscopy and enzyme addition assays (EAAs). The same 0.25 M NaOH and 0.05 M ethylenediaminetetraacetic acid (EDTA) extracts of ten temperate and tropical topsoils under arable crops or permanent grassland were analysed by each method. Additionally, the substrate specificity of the used enzymes was verified through P-31 NMR analysis of one enzyme-treated soil extract. Finally, the molecular weight distribution of organic P was characterised using gel filtration chromatography. NaOH-EDTA extractable organic P ranged from 7 to 1108 mg P kg(-1) soil. Using P-31 NMR spectroscopy, six organic P species in the mono- and diester region plus orthophosphate, pyrophosphate and phosphonates were detected. Deconvolution of P-31 NMR spectra was not possible for two soils due to poor signal to noise ratio. Using EAAs, inositol phosphate-like P was identified as the largest enzyme-labile organic P class in most soils, followed by monoester-like P and DNA-like P. Corresponding classes of organic P determined by P-31 NMR and EAAs were established and concentrations were found to agree well in general. However, repeatability was higher for P-31 NMR spectroscopy than for EAAs. P-31 NMR spectroscopy on an enzyme-treated extract showed that each enzyme acted on the anticipated organic P class, although treatment with phytase caused the appearance of a new and yet unidentified peak in the monoester region. Gel filtration chromatography of alkaline extracts revealed the presence of high-molecular weight organic P (>5 kDa) which had a 1:1 relationship with enzyme-stable P. For both methods, advantages and drawbacks with respect to required sample pre-treatment, analysis time and cost and the total number of identifiable compounds are discussed. While EAAs are suitable for a quick and coarse characterisation of larger sample numbers, P-31 NMR is more robust and allows a more detailed quantification of P forms. (C) 2015 Elsevier Ltd. All rights reserved.