贺兰山丁香对土壤理化性质、酶活性和微生物多样性的影响

【目的】研究濒危植物贺兰山丁香与生长地土壤养分、土壤酶活力和微生物群落的关系,为理解其影响机制提供科学依据。【方法】从贺兰山丁香灌丛下及其附近裸地分别采集3份土壤样品,在测定两组样本的理化性质、酶活性的基础上,基于高通量测序技术分析了两组样本的微生物群落结构。【结果】贺兰山丁香对土壤酸碱度的影响不大,能使水分、有机质、总氮、速效钾、速效氮的含量显著增加(P<0.05),但导致速效磷含量显著降低(P<0.05);使蔗糖酶、脲酶、漆酶的活性显著增加(P<0.05);使土壤中细菌的多样性减少,但对细菌丰富度基本没有影响,使真菌的多样性和丰富度均增加。在微生物的属水平上,贺兰山丁香使细菌中的芽孢杆菌属和真菌中的螺旋聚孢霉属、复膜孢酵母属、木霉属、Paranamyces明显增加,使细菌的鞘氨醇单胞菌属、黄杆菌属和真菌的Lentinula、镰孢菌属、赤霉菌属、Lycogalopsis、土赤壳属、曲霉属、集壶菌属、支顶孢属等类群的微生物明显减少,这些微生物群落的改变与植物生长地土壤的营养成分和土壤酶活力改变息息相关。【结论】贺兰山丁香主要通过影响土壤中真菌的群落结构增加土壤酶活性,通过提高功能细菌的丰富度增加土壤的养分和水分含量,并促进土壤中碳、氮、磷、钾等元素的循环。

Effects of Syringa pinnatifolia var. alanshanica on soil physicochemical properties,enzyme activities and microbial diversity

ObjectiveThis paper aims to study the relationship between the endangered plant Syringa pinnatifolia var. alanshanica and soil nutrients, soil enzyme and soil microorganisms, and provide evidence for understanding its impact mechanism.MethodFive-point sampling method was employed to collect three soil samples (treatment group) under the S. pinnatifolia var. alanshanica shrub and three control samples (control group) from the naked land near the plant. After the physicochemical properties and enzyme activities determination, the microbial community structure was further analyzed via high-throughput sequencing technique.ResultThe soil pH value remained unchanged, while the contents of water, organic matter, total nitrogen, available potassium and nitrogen was increased significantly (P < 0.05), and the available phosphorus content was decreased significantly (P < 0.05) by S. pinnatifolia var. alanshanica. At the same time, the activities of sucrase, urease, and laccase were increased significantly (P < 0.05). Under the S. pinnatifolia var. alanshanica shrub, the diversity of soil bacteria was decreased with the richness of bacteria being almost unchanged, but both the diversity and abundance of fungi were increased significantly. The numbers of Bacillus in bacteria and Saccharomycopsis, Clonostachys, Trichoderma, Paranamyces in fungi were increased by S. pinnatifolia var. alanshanica. However, the numbers of Sphingomonas and Flavobacterium in bacteria, Lentinula, Fusarium, Gibberella, Lycogalopsis, Ilyonectria, Aspergillus, Synchytrium, and Acremonium in fungi were decreased significantly. All the alterations of microorganisms were closely associated with the changes of nutrients and enzymes.ConclusionS. pinnatifolia var. alanshanica increased the activities of soil enzymes by altering the community structure of soil fungi, and enhanced the contents of soil nutrients and water, and promoted the cycling of carbon, nitrogen, phosphorus and potassium by increasing the richness of functional bacteria.