Organic matter protection by kaolinite over bio-decomposition as suggested by lignin and solvent-extractable lipid molecular markers
Organic matter protection by kaolinite over bio-decomposition as suggested by lignin and solvent-extractable lipid molecular markers
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木质素和溶剂可萃取脂质分子标记表明，高岭石对生物分解的有机物具有保护作用
DOI：
10.1016/j.scitotenv.2018.07.456
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发表时间：
2019
影响因子：
9.8
通讯作者：
Steinberg Christian E. W.
中科院分区：
文献类型：
--
作者：
Li Fangfang;Chang Zhaofeng;Khaing Kaythi;Zhou Yuwei;Zhao Haiyun;Liang Ni;Zhou D;an;Pan Bo;Steinberg Christian E. W.
有机-无机复合物的形成是有机质稳定化的关键。然而，有限的研究已经进行了系统的研究矿物对植物残体的分解在分子水平上的影响。在这项研究中，松针和板栗叶与高岭石以5：1的重量比混合。对照是不含高岭石的植物组织。所有样品在实验室中培养一年。分析了分子标记物，包括木质素衍生的酚类（例如Vanilly单元、肉桂基单元和肉桂基单元）和溶剂可提取的脂质（例如正链烷酸、正链烷醇和正烷烃）。木质素衍生的酚类和脂质化合物的浓度高于在高岭石的存在下比没有高岭石。高岭石体系的降解指数（Ad/Al）V（香草酸与香草醛的比值）和CPI（正构烷烃和正构烷烃的碳优先指数）较低。这些结果表明，高岭石减少了OM分解。高岭石的加入也稳定了植物中的一些碳水化合物。此外，OM的降解导致产生持久的自由基，由电子顺磁共振（EPR）信号表示。有高岭石时EPR信号比无高岭石时高。我们推测，吸附的半醌或醌自由基高岭石可能会限制他们与其他OM部分的反应，从而延长其寿命。除了在土壤团聚体中嵌入OM之外，我们的研究结果还为土壤OM的另一种矿物保护机制提供了直接证据。
The formation of organo-mineral complexes is essential in organic matter (OM) stabilization. However, limited studies have been conducted to systematically examine the mineral influence on the decomposition of plant residuals at a molecular level. In this study, pine needles and chestnut leaves were mixed with kaolinite at the weight ratio of 5:1. The controls were plant tissues without kaolinite. All the samples were incubated in the laboratory for one year. Molecular markers, including lignin-derived phenols (e.g. Vanilly units, syringyl units and cinnamyl units) and solvent-extractable lipids (e.g. n-alkanoic acid, n-alkanols and n-alkanes), were analyzed. The concentrations of lignin-derived phenols and lipid compounds were higher in the presence of kaolinite than without kaolinite. Lower degradation indexes, such as (Ad/Al)V(ratio of vanillic acid to vanillin) and CPI (carbon preference index of n-alkanoic acid and n-alkanes), were found in the kaolinite system. These results indicate that kaolinite reduced the OM decomposition. The addition of kaolinite also stabilized some carbohydrates from plants. Furthermore, the degradation of OM led to the generation of persistent free radicals, indicated by electron paramagnetic resonance (EPR) signals. The EPR signals were higher with than without kaolinite. We hypothesize that the adsorption of semiquinone or quinone radicals on kaolinite may limit their reaction with other OM moieties and thus extended their lifetimes. In addition to embedding OM in soil aggregates, our results provide direct evidence of another mineral protective mechanism of soil OM.