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High content and distinct spectroscopic characteristics of water-extractable organic matter in rhizosheath soils in a semiarid grassland

文献类型: 外文期刊

作者: Mo, Xiaohan 1 ; Wang, Mengke 2 ; Wang, Yinghui 2 ; Zhang, Peng 2 ; Zhang, Ang 4 ; Kong, Deliang 5 ; Zeng, Hui 1 ; Wang, Junjian 2 ;

作者机构: 1.Peking Univ, Shenzhen Grad Sch, Sch Urban Planning & Design, Shenzhen 518055, Peoples R China

2.Southern Univ Sci & Technol, State Environm Protect Key Lab Integrated Surface, Sch Environm Sci & Engn, Shenzhen 518055, Peoples R China

3.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Guangdong Prov Key Lab Soil & Groundwater Pollut, Shenzhen 518055, Peoples R China

4.Chinese Acad Trop Agr Sci, Spice & Beverage Res Inst, Wanning 571533, Peoples R China

5.Henan Agr Univ, Coll Forestry, Zhengzhou 450002, Peoples R China

关键词: Carbon cycle; Parallel factor analysis; Rhizosheath; Rhizosphere; Spectroscopy

期刊名称:RHIZOSPHERE ( 影响因子:3.437; )

ISSN:

年卷期: 2022 年 23 卷

页码:

收录情况: SCI

摘要: Rhizosheaths are sheath-like soils widely observed on plant roots and often have higher bioavailability compared with non-rhizosheath rhizosphere soils. As the most labile soil fraction, the quantity and quality of water-extractable organic matter (WEOM) and its temporal dynamics in rhizosheath soils, however, remain unclear. Here, we used ultraviolet-visible and excitation-emission matrix fluorescence spectroscopy to elucidate the WEOM characteristics of rhizosheath and non-rhizosheath soils in an Inner Mongolian grassland and investigate the temporal dynamics of rhizosheath WEOM from early (June) to late (October) growth stages. The results showed that rhizosheath soils had 88% more bulk WEOM (as indicated by water-extractable organic carbon), 44% more chromophoric WEOM, 55% more humus-like (i.e., humic- and fulvic-like) fluorescent WEOM, and 152% more protein-like fluorescent WEOM compared with non-rhizosheath soils. The absorbance and fluorescence analyses revealed that rhizosheath WEOM exhibited lower ammaticity and molecular size and higher fresh microbial contributions. Further, rhizosheath WEOM was more depleted and showed much higher aromaticity and microbial contributions in the middle (August) growth stage that had the highest temperature and precipitation levels. These findings suggest an enrichment of labile organic compounds, which can serve as the primary contributor to the commonly reported high microbial biomass and activity in rhizosheath soils. Overall, the results supported the exceptionally high labile substrate availability for accelerated microbial carbon processing in the rhizosphere microenvimnment of rhizosheath-forming plants.

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