In arid highland environments harsh conditions for vegetation establishment prevail. Plants in these environments develop different strategies to survive, including associations with fungal root endophytes. These associations may improve plant growth, helping plant resistance to adverse environments. The aim of this study was to determine the relationship among arbuscular mycorrhizal fungi (AMF), dark septate endophytes (DSE) and dominance degree of Poaceae in arid highlands of Argentine Puna. We studied AMF and DSE root colonization, and rhizospheric hyphal densities of dominant and subordinate grass species. Dual and positive associations between AMF and DSE prevailed. Dominant grasses had the highest levels of AMF and DSE root colonization. Dominant and intermediate grasses were associated with the highest values of rhizospheric hyphal density. In Puna highlands, the interactions among AMF, DSE and grasses suggest that fungal root endophytes may play a role in structuring grass communities by differentially improving the resistance to harsh conditions.

在干旱的高原环境中，植被建立的恶劣条件普遍存在。在这些环境中，植物会制定不同的生存策略，包括与真菌根部内生菌缔合。这些联系可以改善植物的生长，帮助植物抵抗不利的环境。这项研究的目的是确定在阿根廷Puna干旱高地的丛枝菌根真菌（AMF），深色隔生内生菌（DSE）和禾本科的优势度之间的关系。我们研究了主要和次要草种的AMF和DSE根定植，以及根际菌丝密度。AMF和DSE之间的双重和积极联系盛行。优势草的AMF和DSE根定植水平最高。优势草和中间草与根际菌丝密度的最大值相关。