摘要:半干旱区沙地土壤发育早期依赖固沙植被建成，油蒿和差巴嘎蒿作为我国北方半干旱区沙地半灌木植物群落的主要先锋种和建群种，研究其建成对土壤细菌群落变化的影响对沙质草原生态系统稳定性有重要意义。因此，围绕两个典型的半干旱区（科尔沁沙地和毛乌素沙地），通过高通量测序的方法探讨了蒿类群落生长前后两个阶段（流动沙丘和藓类结皮）的土壤细菌多样性和群落组成变化规律，结果表明：（1）植被建成前后，土壤总碳、总氮、全磷、电导率和含水率均有显著差异，而pH值在不同阶段变化不显著；（2）植被建成前后，土壤细菌多样性变化不显著，但是细菌群落组成在不同阶段具有较大差异。在门类水平上，厚壁菌门（Firmicutes）、拟杆菌（Bacteroidetes）、变形菌门（Proteobacteria）和放线菌（Actinobacteria）均是两个阶段的优势菌，但随着蒿类植被建成和土壤养分的积累，厚壁菌门的相对丰度降低，变形菌门和放线菌门的相对丰度增加；（3）两个阶段，不同深度土壤理化性质和优势菌的相对丰度均存在变化；（4）两种典型沙地土壤理化特性和细菌群落在植被建成前后的变化规律存在共性。通过空间代替时间序列的方法，阐明了土壤细菌群落随着半干旱沙地同类型植被建成的变化模式，可为总结半干旱区植被恢复与成土过程的关系提供参考和思路。



Abstract:In semi-arid regions, the early development of sandy soil relies on the building of sand-fixing vegetation. As one of the main pioneer and constructive species of plant community in the semi-arid area of China, it is of great significance to study the impact of establishment of Artemisia ordosica and A. halodendron on the changes of soil bacterial community and further on the stability of sandy grassland ecosystem. Thus, focused on two typical semi-arid areas (Horqin Sandy Land and Mu Us Sandy Land), this study explored the soil bacteria diversity and community composition changes in two stages (mobile sand dunes and moss crusts) before and after the growth of Artemisia community through high-throughput sequencing. Results showed that: (1) Before and after vegetation built, the soil total carbon, total nitrogen, total phosphorus, electrical conductivity and moisture content all had significant differences, while the pH value did not change at different stages. (2) Before and after vegetation built, the soil bacterial diversity did not change significantly, but the bacterial community composition varied greatly at different stages. At the phylum level, Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant bacteria in these two stages, however, with the building of Artemisia vegetation and the accumulation of nutrients in soil, the relative abundance of Firmicutes was decreased, and the relative abundance of Proteobacteria and Actinobacteria were increased. (3) In both of the two stages, the physicochemical properties and the relative abundance of dominant bacteria were all found to be varied between the different depth samples. (4) The variation trends of the physicochemical properties and bacterial community were quite similar between the two typical sandy lands. By using the method of space instead of time, this study clarified the changes of soil bacterial community along with the same type of vegetation built in semi-arid sandy lands, which could further support data and ideas for summarizing the relationship between vegetation restoration and soil formation in semi-arid areas.





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