Supervisors: prof. Martin Zobel ja vanemteadur Maarja Öpik
Opponent: dr Concepción Azcón González de Aguilar, (Estación Experimental del Zaidín, CSIC, Hispaania)
Arbuscular mycorrhizal (AM) fungi are obligate symbionts in majority of land plants and colonize plant roots and soil around them. For the understanding how plant-AM fungal interactions could function in natural ecosystems, it is important to describe AM fungal distribution and diversity patterns in respect to plant partners and environmental parameters. In this thesis, the AM fungal communities and factors affecting them were studied in boreo-nemoral forest ecosystem. These forests contain mostly ectomycorrhizal trees in tree layer and have a species rich arbuscular mycorrhizal understorey.
The results showed that plant species, measured environmental parameters and forest management had no significant effect on AM fungal taxon richness or community composition in plant roots. AM fungal taxon richness was higher in plant roots than in soil and the intraradical AM fungal community composition was different from that in soil. Furthermore, the AM fungal communities in plant roots are non-randomly assembled and are phylogenetically and potentially functionally similar subsets from the local taxon pool, while the fungi coexisting in soil represent a randomly assembled community.
In conclusion, this thesis revealed that boreonemoral forest ecosystems are important ecosystems in respect of AM taxon richness and that non-random assembly processes may have shaped fungal assemblages in their understorey plant roots.