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

Mo，Xiaohan1,2,3; Wang，Mengke2,3; Wang，Yinghui2,3; Zhang，Peng2,3; Zhang，Ang4; Kong，Deliang5; Zeng，Hui1; Wang，Junjian2,3

2022-09-01

10.1016/j.rhisph.2022.100553

Rhizosphere   Impact Factor & Quartile

2452-2198

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 aromaticity 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 microenvironment of rhizosheath-forming plants.

Carbon cycle Parallel factor analysis Rhizosheath Rhizosphere Spectroscopy

SCI

English

Corresponding

Basic and Applied Basic Research Foundation of Guangdong Province[2021B1515020082];National Natural Science Foundation of China[41807360];National Natural Science Foundation of China[42122054];National Natural Science Foundation of China[42192513];VNU Science and Technology Development Fund[JCYJ20190809142611503];VNU Science and Technology Development Fund[JCYJ20190809162205531];

Agriculture ; Plant Sciences

Agronomy ; Plant Sciences ; Soil Science

WOS:000836470900004

ELSEVIER

2-s2.0-85132515435

Scopus

1.School of Urban Planning and Design,Peking University Shenzhen Graduate School,Peking University,Shenzhen,518055,China
2.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
3.Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
4.Spice and Beverage Research Institute,Chinese Academy of Tropical Agricultural Sciences,Wanning,571533,China
5.College of Forestry,Henan Agricultural University,Zhengzhou,450002,China

Mo，Xiaohan,Wang，Mengke,Wang，Yinghui,et al. High content and distinct spectroscopic characteristics of water-extractable organic matter in rhizosheath soils in a semiarid grassland[J]. Rhizosphere,2022,23.

Mo，Xiaohan.,Wang，Mengke.,Wang，Yinghui.,Zhang，Peng.,Zhang，Ang.,...&Wang，Junjian.(2022).High content and distinct spectroscopic characteristics of water-extractable organic matter in rhizosheath soils in a semiarid grassland.Rhizosphere,23.

Mo，Xiaohan,et al."High content and distinct spectroscopic characteristics of water-extractable organic matter in rhizosheath soils in a semiarid grassland".Rhizosphere 23(2022).