Arbuscular mycorrhizal fungal diversity patterns in boreonemoral forest ecosystems
Date
2013-11-20
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Abstract
Arbuskulaar-mükoriissed (AM) seened on enamuse maismaataimede obligatoorsed sümbiondid ning koloniseerivad taimejuuri ja mulda nende ümber. Et mõista taimede ja AM seente vahelisi suhteid looduslikes ökosüsteemides, on oluline kirjeldada AM seente levikut ja mitmekesisuse mustreid ning viimaste seoseid taimpartnerite ja keskkonnaparameetritega. Käesoleva doktoritöös uuriti AM seente kooslusi ning neid mõjutavaid tegureid salumetsa ökosüsteemis, kus puurindes domineerivad peamiselt ektomükoriisat moodustavad okas- ja lehtpuud, kuid esineb väga liigirikas arbuskulaarset mükoriisat moodustav alustaimestik.
Tulemustest selgus, et AM seente mitmekesisus salumetsa alustaimestiku juurtes oli suur. Taimeliik, mõõdetud keskkonnaparameetrid ning metsa majandamine ei omanud olulist mõju AM seente liigirikkusele ega koosluse koosseisule taimejuurtes. AM seente liigirikkus taimejuurtes oli tunduvalt suurem kui mullas ning koosluse koosseis taimejuurtes ja mullas oli erinev. Lisaks, olid taimejuurtest tuvastatud AM seente kooslused olid moodustunud kohaliku AM seente kogumi fülogeneetiliselt sarnasematest liikidest. Samas, mullast leitud AM seente kooslus esindab kohalike AM seente hulgast juhuslikult moodustunud kooslust.
Kokkuvõtvalt näitas käesolev doktoritöö, et salumetsad on AM seente mitmekesisuse osas olulised ökosüsteemid ning nende alustaimestiku juurtes kujunevaid AM seente kooslusi mõjutavad mittejuhuslikud protsessid.
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.
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.
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