Arbuscular Mycorrhizal Fungi and Glomalin Play a Crucial Role in Soil Aggregate Stability in Pb-Contaminated Soil

Yinong Li; Jiazheng Xu; Jin Hu; Tianyu Zhang; Xuefeng Wu; Yurong Yang

doi:10.3390/ijerph19095029

Arbuscular Mycorrhizal Fungi and Glomalin Play a Crucial Role in Soil Aggregate Stability in Pb-Contaminated Soil

Int J Environ Res Public Health. 2022 Apr 21;19(9):5029. doi: 10.3390/ijerph19095029.

Authors

Yinong Li¹, Jiazheng Xu^{1

2}, Jin Hu¹, Tianyu Zhang¹, Xuefeng Wu¹, Yurong Yang^{1

2}

Affiliations

¹ Key Laboratory of Vegetation Ecology of the Ministry of Education, Institute of Grassland Science, Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun 130024, China.
² State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China.

Abstract

With the rapid development of industrialization and urbanization, soil contamination with heavy metal (HM) has gradually become a global environmental problem. Lead (Pb) is one of the most abundant toxic metals in soil and high concentrations of Pb can inhibit plant growth, harm human health, and damage soil properties, including quality and stability. Arbuscular mycorrhizal fungi (AMF) are a type of obligate symbiotic soil microorganism forming symbiotic associations with most terrestrial plants, which play an essential role in the remediation of HM-polluted soils. In this study, we investigated the effects of AMF on the stability of soil aggregates under Pb stress in a pot experiment. The results showed that the hyphal density (HLD) and spore density (SPD) of the AMF in the soil were significantly reduced at Pb stress levels of 1000 mg kg−1 and 2000 mg kg−1. AMF inoculation strongly improved the concentration of glomalin-related soil protein (GRSP). The percentage of soil particles >2 mm and 2−1 mm in the AMF-inoculation treatment was higher than that in the non-AMF-inoculation treatment, while the Pb stress increased the percentage of soil particles <0.053 mm and 0.25−0.53 mm. HLD, total glomalin-related soil protein (T-GRSP), and easily extractable glomalin-related soil protein (EE-GRSP) were the three dominant factors regulating the stability of the soil aggregates, based on the random forest model analysis. Furthermore, the structural equation modeling analysis indicated that the Pb stress exerted an indirect effect on the soil-aggregate stability by regulating the HLD or the GRSP, while only the GRSP had a direct effect on the mean weight diameter (MWD) and geometric mean diameter (GMD). The current study increases the understanding of the mechanism through which soil degradation is caused by Pb stress, and emphasizes the crucial importance of glomalin in maintaining the soil-aggregate stability in HM-contaminated ecosystems.

Keywords: glomalin; heavy metal; lead (Pb) pollution; soil aggregation; symbiotic fungi.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ecosystem
Environmental Pollution / analysis
Humans
Lead / analysis
Metals, Heavy* / analysis
Mycorrhizae* / metabolism
Soil / chemistry
Soil Pollutants* / analysis

Substances

Metals, Heavy
Soil
Soil Pollutants
Lead