内蒙古大青山土庄绣线菊根围丛枝菌根真菌群落垂直分布特征

Vertical distribution of arbuscular mycorrhizal fungal community in the rhizosphere of Spiraea pubescens in Daqingshan Mountains, Inner Mongolia

土庄绣线菊Spiraea pubescens是内蒙古大青山干旱地区重要的护土灌木,以水磨村垂直分布(海拔1 515m,1 410m,1 305m)的土庄绣线菊根围土壤和根系为研究对象,分析丛枝菌根真菌(arbuscular mycorrhiza fungi,AMF)菌根侵染率、孢子密度、多样性及群落组成。结果表明,孢子密度和菌根侵染率在海拔1 515m处显著高于海拔1 410m和1 305m处,丛枝丰度在3个海拔间无显著差异。Illumina MiSeq测序共得到71个AMF OTUs(operational taxonomic units)。不同海拔优势属均为Glomus,且AMF群落组成存在显著差异。Margalef丰富度指数、Chao 1丰富度指数和Shannon‐Wiener多样性指数均随海拔升高而升高,海拔1 515m处显著高于海拔1 410m和1 305m处,Simpson多样性指数在不同海拔间无显著差异。土壤有机质和植被盖度与孢子密度呈显著负相关;速效磷、含水量和植被盖度与菌根侵染率呈显著负相关;海拔与Shannon‐Wiener多样性指数、Simpson多样性指数、Chao 1丰富度指数和Margalef丰富度指数呈显著正相关,而速效磷和植被盖度与其呈显著负相关。研究结果为进一步探索AMF对土庄绣线菊在干旱环境中生存发挥的作用奠定理论基础。

Spireee pubescens is an important soil retaining shrub which widely grows in arid environment of Daqingshan Mountains, Inner Mongolia. Rhizosphere soil and roots of 5. pubescens at different altitudes （1 515m, 1 410m and 1 305m above sea level） in Shuimocun were collected to analyze colonization rate, spore density, diversity and community composition of arbuscular mycorrhizal fungi （AMF）. The results showed that spore density and colonization rate were significantly higher at alt 1 515m than those at alt. 1 410m and 1 30Sm, while arbuscular abundance had no significant difference in different altitudes. A total of 71 AMF OTUs （operational taxonomic units） were detected in all soil samples by Illumina MiSeq sequencing. Glomus was the dominant genus, and AMF community composition was significantly different in different altitudes. Margalef index, Chao 1 ndex and Shannon-Wiener index increased with the increase of altitude, which were significantly higher at alt. 1 515m than at alt. 1 410m and 1 305m. No significant difference was observed in Simpson index in different altitudes. Soil organic matter and plant cover were significantly negatively correlated with spore density. Available phosphorus, water content and plant cover were significantly ne ndex were significan gat tly vely correlated with colonization rate. Shannon-Wiener, Simpson index, Margalef index and Chao t positively correlated with elevation, but significantly negatively correlated with available phosphorus and plant cover. The results would provide important scientific basis to further discuss the effects of AMF on the survival of 5 pubescens in arid areas