藏北高寒草原土壤活性有机碳对AM真菌物种多样性的影响

基于孢子形态学鉴定，通过研究土壤活性有机碳（ASOC）质量分数对丛枝菌根真菌（AMF）物种多样性及侵染效应的影响，为基于土壤环境调控的菌根生物技术的应用探寻新的途径和方法。结果表明，ASOC质量分数在0.30～0.80、0.81～1.40、1.41～4.00 g/kg范围内，Glomus属真菌对AMF的种群构成均具重要作用，且其影响随ASOC质量分数的增加而提高；由Glomus属真菌构成的优势种，特别是一些共有优势种对AMF的种群发育具有主导作用；ASOC质量分数与孢子密度呈显著正相关，较低的ASOC质量分数极显著促进了菌根侵染。从综合影响看，调控ASOC质量分数至较低（0.81～1.40 g/kg）水平，可能充分发挥AMF在高寒草原中的重要作用，这为探寻适度的农业工程调控措施，以强化ASOC对AMF物种多样性及菌根侵染的重要影响，促进多菌种以及多优势种的协同作用，稳定高寒草原环境提供了重要信息。

Effect of ASOC on diversity of arbuscular mycorrhizal fungi in alpine steppe of north Tibet

Spore identification technique was employed to understand the effect of active soil organic carbon (ASOC) on the biodiversity and colonization indices of arbuscular mycorrhizal fungi (AMF). The results showed that within ASOC mass fraction ranges, Glomus had significant effect on community composition of AMF and the effect was enhanced with the increase of ASOC. Dominant species (in particular some co-occurring dominant species played an important role in community structure of AMF. ASOC mass fraction was positively correlated with spore density, and the colonization intensity and arbuscule richness were increased at the lower and intermediate ASOC mass fractions. The overall effect of AMF was great at lower ASOC level (0.81~1.40 g/kg) Our results indicate the application of AMF may have great potential in alpine steppe at lower ASOC level. This provides important information for developing suitable agricultural engineering techniques and methods to reinforce the effect of ASOC on biodiversity and infection intensity of AMF, and to increase the synergetic effects among multiple mycorrhizal species and dominant species. The result is of great significance for the sustainability of the alpine grasslands.