Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2

Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO 2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM fungus were grown in two glasshouse cells with different CO 2 concentrations (400 and 700 ppm) for 10 weeks. A 15 N isotope labeling technique was used to trace plant N uptake. Results showed that elevated CO 2 increased AM fungal colonization. Under CO 2 elevation, AM plants had higher C concentration and higher plant biomass than the non-AM plants. CO 2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, 15 N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants than in non-AM controls under CO 2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO 2 .