秦岭火地塘真菌群落海拔分布格局

土壤真菌在自然生态系统的养分循环和土壤碳储存方面起重要作用。秦岭火地塘林区在不同海拔分布着不同的优势树种,但其相应的土壤特征及微生物群落的海拔分布格局仍不明晰。本研究分析了5个海拔处(1500、1700、1900、2100和2300 m)的土壤特征变化趋势,并在高通量测序基础上研究了真菌群落格局。结果表明: 土壤有效磷含量、pH值随海拔的增加而显著增加,土壤水分则呈下降趋势。土壤真菌Shannon多样性指数随海拔升高呈下降趋势,而ACE丰度指数相反;真菌优势门为担子菌门(68.2%)、子囊菌门(19.8%)和球囊菌门(1.7%),且随海拔升高整体呈现出“U”型或“单峰”变化格局;真菌优势纲为伞菌纲(64.2%)、粪壳菌纲(5.8%)和锤舌菌纲(4.1%)。冗余分析(RDA)表明,土壤特性解释了土壤真菌群落总变异的89.1%,其中土壤有效磷含量、pH和海拔是土壤真菌群落海拔梯度变化的主要驱动因子。在秦岭火地塘林区,土壤特征在海拔梯度上的差异性影响了土壤真菌群落组成。

Altitude distribution of fungal community in Huoditang in Qinling Mountains,Northwest China

Soil fungi play an important role in soil nutrient cycling and carbon storage in natural ecosystems. Dominant tree species showed altitude distribution in Huoditang forest in Qinling Mountains, whereas the corresponding changes of soil characteristics and microbial communities are still unclear. In this study, the variations of soil characteristics were investigated at five altitudes (1500, 1700, 1900, 2100 and 2300 m). The collected soil samples were sequenced by Illumina MiSeq sequencing platform, and the pattern of fungal community was studied. The results showed that soil available phosphorus concentration (AP) and soil pH increased significantly whereas soil moisture showed a downward trend with increasing altitude. The Shannon diversity index of soil fungi decreased and ACE richness index showed an opposite trend with increasing altitude. Basidiomycota (68.2%), Ascomycota (19.9%), and Mortierellomycota (1.7%) were dominant fungal phyla, which showed a ‘U' shape or ‘peak' pattern according to altitude. Agaricomycetes (64.2%), Sordariomycetes (5.8%), and Leotiomycetes (4.1%) were the dominant fungal classes. Results of redundancy analysis (RDA) showed that 89.1% of the total variations of soil fungal community were explained by soil characteristics, while AP, pH and altitude were the main driving factors for altitude variations of soil fungal communities. Soil characteristics had certain differences with altitude changes in Huoditang forest region in Qinling Mountains, which affected soil fungal community composition.