Effect Of Arbuscular Mycorrhizal Fungi On The Growth Of Shubs And Grasses In Kubuqi Desert

Desertification has been an increasing threat to global environment due to climate change,improper land uses and resource exploitation in the past decades.China is among the most venerable countries to desertification,yet the efforts on desertification control have been mostly focused on the establishment of aboveground vegetation with little attention on the important roles belowground microbes may play on the restoration of desert ecosystems.As a group of most widespread soil microorgnisms in terrestrial ecosystems,arbuscular mycorrhizal fungi(AMF)can help host plants gain water and nutrients,enhance the growth of plants and improve plant's resistance to water stress.Since different plants often host different AMF communities that vary in species composition,and different AMF assemblages often provide different benefits to host plants,we hypostasize that AMF associated with different desert plants may function differently in terms of improving the performance of native plants in desert ecosystems.In this study,we chose six most common shrub and grasses species native to Kubuqi desert as target plants,including Caragana korshinskii,Hedysarum fruticosum var.mongolicum,Caragana microphylla,Salix cheilophila,Poa annua and Melilotus officinalis.We sampled rhizosphere soil under individuals of Caragana korshinskii,Hedysarum fruticosum var.mongolicum,Caragana microphylla,Salix cheilophila,Poa annua and Artemisia ordosica from field as AMF inocula.In greenhouse,we reciprocally inoculated seedlings of each target plant species with AMF inoclua collected from six different plant species.The plants in greenhouse were maintained under drought stress similar to field conditions.Upon harvest after a growing season,we measured the aboveground and belowground biomass,leaf water potential and photosynthetic potential of each plant species in order to assess the effects of AMF on the growth and physiology of common desert plantsOur results demonstrated that AMF associated with Poa annua significantly increased the aboveground biomass of Caragana korshinskii,Hedysarum fruticosum var.mongolicum,Caragana microphylla,Poa annua and Melilotus officinalis comparing to non-AMF controls,and the maximum increase reached to 444%.AMF had no significant effects on belowground biomass,leaf water potential and photosynthetic potential of desert plants,indicating that these symbionts provided little drought resistant benefits to host plants.We conclude that although native AMF can enhance the growth of desert plants,mycorrhizal benefits can be overshadowed by plant's physiological stress under extreme drought conditions.