河北省同纬度不同样地土壤盐分特征与微生物群落结构研究

Soil salt characteristics and microbial community structures in different regions at the same latitude of Hebei Province

摘要:

目的 探究不同盐分类型土壤微生物群落结构特征及其与盐分离子的关联性，为盐碱土壤改良提供理论依据。方法 沿北纬38°采集石家庄(LC)、衡水(SZ)和沧州(HX) 3个地区的土壤样品，测定样品中水溶性总盐含量(total content of water-soluble salt, TSS)、盐分离子、酶活性及微生物群落结构，并采用Mantel分析法研究土壤盐分特征与微生物群落结构的相关性。结果 在LC、SZ和HX 3个样地中，土壤电导率(electrical conductance, EC)、TSS、Na⁺、Cl^-、SO₄^2-和NO₃^-含量均呈显著增加趋势，而土壤蔗糖酶(invertase, SC)、碱性磷酸酶(alkaline phosphatase, ALP)、脲酶(urease, UE)和过氧化氢酶(catalase, CAT) 4种酶的活性则显著降低，表明盐碱土壤中养分循环受到抑制。3个盐分类型的土壤细菌和真菌群落β多样性差异显著，其中SZ的细菌和真菌α多样性与LC存在显著差异。HX土壤中嗜盐的芽单胞菌门(Gemmatimonadota)、粘菌门(Myxococcota)及具有尿素分解(ureolysis)功能的菌群丰度显著升高，而氮固定(nitrogen fixation)菌群丰度降低。Mantel分析表明，Na?、Cl?等盐分离子与微生物群落组成呈显著负相关，但与耐盐菌(如Gemmatimonadota)呈正相关。结论 不同盐分类型土壤微生物群落存在显著差异，土壤中盐分离子通过抑制非耐盐菌和选择性富集耐盐菌驱动群落结构变化。微生物群落的改变和土壤酶活性的降低是盐碱土壤养分循环和供应障碍的关键因素，该研究为盐碱土壤改良中关键菌群的调控提供了理论依据。

关键词:土壤盐分;微生物群落;高通量测序;相关性分析

Abstract:

Objective To investigate the structural characteristics of microbial communities in the soil samples with varying salt types and their associations with salt ions, thus laying a theoretical foundation for the amelioration of saline-alkali soil.Methods Soil samples were collected from three regions: Shijiazhuang (LC), Hengshui (SZ), and Cangzhou (HX) at 38°N. The total soluble salt content (TSS), salt ions, enzyme activities, and microbial community structures were measured. Mantel analysis was performed to examine the correlations between soil salt characteristics and microbial community structures.Results In the LC, SZ, and HX regions, the levels of soil electric conductivity, TSS, Na⁺, Cl^-, SO₄^2-, and NO₃^- showed a significant increasing trend, while the activities of four soil enzymes (invertase, alkaline phosphate, urease, and catalase) exhibited significant decreases, indicating that nutrient cycling was inhibited in saline-alkali soil. The β diversity of bacteria and fungi exhibited significant differences among the soil samples of three salt types. The α diversity of both bacteria and fungi in SZ showed significant differences from that in LC. In HX, the abundance of halophilic phyla such as Gemmatimonadota and Myxococcota, as well as the taxa with the function of ureolysis, significantly increased, while that of nitrogen-fixing taxa decreased. Mantel analysis indicated that salt ions such as Na⁺ and Cl^- had significantly negative correlations with microbial community composition but positive correlations with halophilic bacteria, such as Gemmatimonadota.Conclusion Microbial communities in the soil samples with different salt types exhibited significant differences. Salt ions drove structural changes of microbial communities in soil by inhibiting non-halophilic microorganisms and selectively enriching halophilic species. The alterations in microbial communities and the reduction in soil enzyme activities are key factors contributing to the impairment of nutrient cycling and supply in saline-alkali soil. This study lays a theoretical foundation for the regulation of key microbial populations in the amelioration of saline-alkali soil.

Key words:soil salt;microbial community;high-throughput sequencing;correlation analysis