Arbuscular mycorrhizal (AM) fungi usually improve plant performance yet our knowledge
about their effects on seed germination and early plant establishment is very limited. We
performed a factorial greenhouse experiment where the seeds from four low Arctic cooccurring
mycorrhizal herbs (Antennaria dioica, Campanula rotundifolia, Sibbaldia
procumbens, and Solidago virgaurea) were germinated alone or in the vicinity of an adult
Sibbaldia plant with or without AM fungi; given either as spores or being present in a
common mycorrhizal network (CMN). Three different AM fungal species were examined to
assess species-specific differences in symbiont acquisition rate. Out of the four plant species
investigated, the presence of AM fungi affected seed germination only in Campanula and this
effect was dependent on whether the AM fungi were present in the soil as spores or as a
CMN. Overall, after germination, developing seedlings showed AM fungal colonization in
their roots as soon as 2 days after cotyledon emergence. Our results show that CMN may
provide germinating seedlings faster acquisition of the AM fungal partner in comparison to
acquisition from spores. Furthermore, there were AM species-specific differences in the
symbiont acquisition rate highlighting the importance of species identity in AM interactions.
These findings suggest that while AM fungi may not play a fundamental role during seed
germination, plant community composition may be affected by the species-specific AM
fungal effects on seedling establishment and CMN acquisition
