School of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, China.
Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo, 454000, Henan Province, China.
Environ Sci Pollut Res Int. 2020 Oct;27(29):36439-36449. doi: 10.1007/s11356-020-09600-8. Epub 2020 Jun 19.
Dissolved organic matter (DOM) derived from leaf litter plays an important role in maintaining carbon (C) and nitrogen (N) circulation between soils and plants, energy flow, and signaling pathways for plant-microbe interactions of terrestrial ecosystem. In this study, four DOM samples extracted with a 40:1 (v/w) water to sample ratio from the leaf litter of Populus simonii (S1), Artemisia desertorum (S2), Salix cheilophila (S3), and Populus tomentosa (S4) were investigated using the technologies of ultraviolet-visible (UV-Vis) and excitation-emission matrix (EEM) fluorescence spectroscopy. Results showed that the electricity (EC) values of four DOM extracts were significantly different due to the different composition and salt content of each plant. The values of chemical oxygen demand (COD), dissolved organic carbon (DOC), and the sum of values of all peaks' intensities divided by DOC (FI) indicated the higher contents of organic matter in the acid DOM extracts from S1, S2, and S3 (sand-fixing plants) than the neutral DOM extracted from S4. The absorbance shoulder between 250 and 285 nm in the UV-Vis spectra and EEM fluorescence spectra of each sample suggested the presence of many different chromophores such as aromatic or phenolic compounds in plant DOM. According to fluorescence regional integration (FRI) and peak picking results, the content of protein-like materials was higher than that of humic-like substances in DOM from S1, S2, and S3 while the opposite phenomena occurred in DOM from S4. Hence, the physicochemical and fluorescence characterization of DOM extracted from the genus Populus of the family Salicaceae S1 and S4 growing under different edaphic and climatic conditions changed much. The findings would be of great significance to understand the origin, composition, dynamics, and biotransformation of DOM in soils formed in different climatic environments.
溶解有机物质（DOM）来源于落叶，在维持土壤与植物之间的碳（C）和氮（N）循环、能量流动以及陆地生态系统植物-微生物相互作用的信号通路方面发挥着重要作用。在这项研究中，使用紫外-可见（UV-Vis）和激发-发射矩阵（EEM）荧光光谱技术，从泡桐（S1）、沙蒿（S2）、河柳（S3）和毛白杨（S4）的落叶中以 40:1（v/w）的水与样品比提取了四个 DOM 样品，并对其进行了研究。结果表明，由于每种植物的组成和盐分含量不同，四个 DOM 提取物的电导率（EC）值存在显著差异。化学需氧量（COD）、溶解有机碳（DOC）和所有峰强度之和除以 DOC 的值（FI）表明，S1、S2 和 S3（固沙植物）的酸性 DOM 提取物中的有机物含量高于 S4 的中性 DOM 提取物。每个样品的 UV-Vis 光谱和 EEM 荧光光谱中 250 到 285nm 之间的吸收肩说明在植物 DOM 中存在许多不同的发色团，如芳香族或酚类化合物。根据荧光区域积分（FRI）和峰选择结果，在 S1、S2 和 S3 的 DOM 中，类蛋白物质的含量高于类腐殖质物质，而在 S4 的 DOM 中则相反。因此，在不同土壤和气候条件下生长的柳属和杨属植物提取的 DOM 的物理化学和荧光特性发生了很大变化。这些发现对于理解不同气候环境下形成的土壤中 DOM 的来源、组成、动态和生物转化具有重要意义。
