Influence of plants and environmental variables on the diversity of soil microbial communities in the Yellow River Delta Wetland, China

Microorganisms play an important role in the biogeochemical cycle and ecological function regulation of wetlands, have a major impact on global climate change and are critical for maintaining the health of the global ecosystem. In order to investigate the relationships among plants, environmental variables, and microbial communities in coastal wetlands in the Yellow River Delta, we selected soils growing plants such as Suaeda salsa, Tamarix chinensis, Phragmites australis, and cotton etc. The results show that there were differences in microbial diversity among areas with different vegetation cover and the microbial abundance in Phragmites australis and Tamarix chinensis areas was higher than that in mudflat, Suaeda glauca and cotton field, plants increased the diversity of soil microorganisms. The structure and diversity of soil microorganisms were significantly higher than that of endophytes. The Shannon index of soil bacteria was about 4-5.5, while that of endophytes was about 0-4. The soil bacteria were mainly Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria, accounting for more than 90.0% in all samples. The Mn4+, Fe3+ and hydrolytic nitrogen contents in the soil of vegetation covered areas was lower than that of the bare beach, the content of hydrolytic nitrogen in Phragmites australis area was generally higher, and the content of SO42- and NO2- in the area was lowest near oil fields. Redundancy analysis shows that the explanatory rates of environmental factors at the phylum and genus levels were 89.70% and 86.80%, respectively, and K (23.40%), NO2- (11.80%), Mn-4(+) (9.80%) and Na (8.00%) were the main factors explaining the structural changes and composition of microbial flora at the phylum level. This study provides an ecological perspective for understanding the influence mechanism between wetland microbial diversity and wetland ecosystem function. It is helpful for us to understand the interactions among plants, environmental variables, and microbial communities in the coastal wetland of the Yellow River Delta, and has important guiding significance for the scientific research of soil environmental remediation in the degraded coastal wetland of the Yellow River Delta. (C) 2020 The Author(s).