Experimental assessment of forest floor geophyte and hemicryptophyte impact on arbuscular mycorrhizal fungi communities

Purpose Herbaceous plants are important components of temperate forest structure and its functioning, however, their impacts on arbuscular mycorrhizal fungi (AMF) remain largely unexplored. We studied the influence of forest herbaceous plant species on AMF abundance, morphospecies richness, and community composition in soil. Methods We tested the influence of plant species identity in an outdoor mesocosm experiment, using two soils, differing in physicochemical properties, planted with four plant species of contrasting traits related to morphology, phenology, reproduction, and ecology; the hemicryptophyte, summer-green Aegopodium podagraria, and spring ephemeral geophytes comprising Allium ursinum, Anemone nemorosa, and Ficaria verna. The plants were grown on both soils in four monocultures, in a combination of A. podagraria and A. ursinum, and a mixture of all four species. Results Aegopodium podagraria and A. ursinum promoted AMF abundance and diversity the most. Higher AMF root colonization and/or soil concentrations of AMF structural and storage markers 16:1 omega 5 PLFA and NLFA, as well as higher AMF spore and morphospecies numbers were found in the A. podagraria and A. ursinum monocultures and mixture. The short period of photosynthetic activity of A. ursinum due to rapid leaf decay does not negatively affect the symbiosis with AMF. Although A. nemorosa and F. verna are mycorrhizal, their effect on AMF in soil was weak. Conclusions The plant impact on AMF may be related to the differences in plant coverage and the character of their interactions with AMF. The herbaceous plants can form niches in soil differing in AMF abundance and diversity.