Effects Of Arbuscular Mycorrhizal Fungi On Intraspecific Competition Of Ligularia Virgaurea And Interspecific Competition Between Ligularia Virgaurea And Elymus Nutans

Ligularia virgaurea,which belong to Ligularia of Compositae is a kind of injurious weed.L.virgaurea have two progenitive ability,sexual propagation and asexual reproduction.Because of overused by herd,the grassland have been degeneration in Gannan Alpine meadow ecosystem.Elymus nutans,which belong to Elymus of Gramineae,is a kind of high quality grazing grass.E.nutans and L.virgaurea are growing together with each other in natural habitats.There must be interspectfic competition between them for the limited resources.Arbuscular mycorrhizal(AM) fungi are ubiquitous in terrestrial plant communities,forming symbiotic association with the roots of the majority of plant species.Arbuscular mycorrhizae play a key role in natural ecosystems and influence plant productivity, plant nutrition acquisition and plant community structure.In order to discover the effects of AM on intraspecific competition of L.virgaurea and interspecific competition between L.virgaurea and E.nutans,pot-planting experiments were carried out.1) AM fungi have significant influenced on intraspecific competition of L. virgaurea.AM fungi decreased the growth of established plants,but could improving N content.At higher density of established plants,AM fungi improve P nutrition absorbed.When in higher density of established plants treatments,the biomass of seedlings significantly increased by AM fungi.N content of seedling also improved by AM fungi while P content have not significant influenced.AM fungi could improve the seedling growth though the arbuscular mycorrhizal network with established plants.2) Biomass of L.virgaurea is decreased by AM fungi in the experiment of interspecific competition between L.virgaurea and E.nutans.The N content in the above-ground of L.virgaurea reduced by AM fungi.As the density of E.nutans decreased,AM fungi restrained the biomass of E.nutans firstly and then improved. AM fungi reduced E.nutans all the time and have no significent influence on P content.3) The survival of L.virgaurea seedlings were very low in the experiment of interspecific competition with E.nutans.The reason may be was that the seedlings of E.nutans caused the seedlings of L.virgaurea to death.AM fungi have no signifant influence on the biomass of E.nutans,but decreased N content.At low density of E, nutans,AM fungi improved P content of E.nutans,but there are not signifant difference at high density treatments.