Arbuscular Mycorrhizal Fungi Promote Plant Growth Of Leymus Chinensis And Increase The Metabolomics Activity Under Nitrogen Addition

Nitrogen(N)deposition has been influencing ecological process,for instance N deposition can affect plant growth and then alter plant community composition.Arbuscular mycorrhizal fungi(AMF)is one of the important soil microbiotas,which plays a key role in plant growth,especially under harsh environmental conditions.However,the effects of AMF on plant growth under N addition are still not well understood.To investigate the mechanism how AMF affect plant growth under N addition,a microcosm experiment was conducted with four N addition levels.The results showed that under N addition AMF significantly increased aboveground biomass of Leymus chinensis,AMF increased aboveground biomass of L.chinensis by 21.5 % and 4.8% under with and without N addition,respectively.AMF expressively improved the net photosynthetic rate(A)by 44% and 29%,soluble protein by 65% and 40% under with and without N additions,respectively.The chlorophyll a,chlorophyll b,chlorophyll a+b and carotenoids content in leaves treated by AMF were greater than in those without AMF treatment.AMF also significantly increased the metabolomics enzymes glutamine oxoglutarate aminotransferase(GOGAT),Glutamine synthetase(GS)and nitrogen reductase(NR)activity under N addition.However,the level of glutamate dehydrogenase(GDH),alanine transaminase(GPT)and soluble carbohydrates(SC)increased significantly under N addition in non-inoculated AMF plants.The result showed that the response of AMF to L.chinensis was stronger than nitrogen deposition,which indicates that AMF could increase plant growth by improving photosynthetic characters and affecting metabolomics enzymes of L.chinensis under Nitrogen addition.