Arbuscular mycorrhizal fungi (AMF) colonize the roots of numerous aquatic and wetland plants, but the establishment and functioning of mycorrhizal symbiosis in submerged habitats have received only little attention. Three pot experiments were conducted to study the interaction of isoetid plants with native AMF. In the first experiment, arbuscular mycorrhizal (AM) symbiosis did not establish in roots of Isoëtes echinospora and I. lacustris, while Littorella uniflora roots were highly colonized. Shoot and root biomass of L. uniflora were, however, not affected by AMF inoculation, and only one of nine AMF isolates significantly increased shoot P concentration. In the second experiment, we compared colonization by three Glomus tetrastratosum isolates of different cultivation history and origin (aquatic versus terrestrial) and their effects on L. uniflora growth and phosphorus nutrition under submerged versus terrestrial conditions. The submerged cultivation considerably slowed, but did not inhibit mycorrhizal root colonization, regardless of isolate identity. Inoculation with any AMF isolate improved plant growth and P uptake under terrestrial, but not submerged conditions. In the final experiment, we compared the communities of AMF established in two cultivation regimes of trap cultures with lake sediments, either submerged on L. uniflora or terrestrial on Zea mays. After 2-year cultivation, we did not detect a significant effect of cultivation regime on AMF community composition. In summary, although submerged conditions do not preclude the development of functional AM symbiosis, the contribution of these symbiotic fungi to the fitness of their hosts seems to be considerably less than under terrestrial conditions.

丛枝菌根真菌（AMF）定居在许多水生和湿地植物的根部，但是在淹没的生境中菌根共生的建立和功能受到的关注很少。进行了三个盆实验，以研究异构植物与天然AMF的相互作用。在第一个实验中，丛枝菌根（AM）共生未在棘齿I和漆树的根中建立，而独花小提琴的根却高度定居。然而，单花乳杆菌的芽和根生物量不受AMF接种的影响，并且九种AMF分离株中只有一种显着增加了芽P的浓度。在第二个实验中，我们比较了三个殖民地在水下和陆地条件下，不同栽培历史和起源（水生或陆生）的Glomus tetrastratosum分离株及其对独生L. uniflora生长和磷营养的影响。淹没的耕种明显减慢了速度，但没有抑制菌根根定殖，无论分离株的身份如何。接种任何AMF分离株都能改善植物生长和在陆地条件下（但不是在淹没条件下）吸收磷。在最后的实验中，我们比较了在两种诱集培养方式下建立的AMF群落与湖泊沉积物的关系，这些沉积物淹没在单花L.或陆生在玉米上。经过2年的耕种，我们没有发现耕种制度对AMF群落组成的显着影响。总之，尽管淹没条件并不妨碍功能性AM共生的发展，但这些共生真菌对宿主适应性的贡献似乎要比陆地条件下的要少。