title: Nitrogen availability drives the effect of Glomus intraradices on the growth of strawberry (Fragaria x ananassa Duch.) plants.
abstract: BACKGROUND
  On the one hand, the critical nitrogen (N) content curve allows the minimal N content necessary for maximum growth rate at any stage of crop development to be predicted. On the other hand, arbuscular mycorrhizal fungi (AMF) transfer N from the soil to the plants and its growth and activity depends on the availability of soil N. Our objective was to investigate how the availability of N in the soil affects growth and the accumulation of N in inoculated strawberry plants. Root colonisation, dry matter accumulation and the critical N% curve were studied during growth of inoculated and non-inoculated strawberry plants grown at several N levels.
  
  
  RESULTS
  (1) The increase in the availability of N augmented root colonisation by AMF. (2) The effect of AMF on plant growth depended on N availability and the plant developmental status. (3) The critical %N curves were fitted by the following equations: %N = 2.81× (DM)(-0.21) (r² = 0.81) and %N = 2.89× (DM)(-0.32) (r² = 0.80) for inoculated and non-inoculated plants, respectively (where DM is the weight of leaf dry matter, in g plant⁻¹).
  
  
  CONCLUSIONS
  N availability was a key factor for root colonisation by AMF and for its contribution to plant growth. The patterns of the critical %N curves suggest that AMF modified the photosynthetic N use efficiency.
authors.affiliation: Corporativo de Desarrollo Sustentable SA de CV, Circuito Parque Industrial 252, Morelia, Michoacán, Mexico.
authors.forename: Vilma
authors.initials: V
authors.lastname: Castellanos-Morales
authors.forename: Javier
authors.initials: J
authors.lastname: Villegas-Moreno
authors.forename: Horst
authors.initials: H
authors.lastname: Vierheilig
authors.forename: Raúl
authors.initials: R
authors.lastname: Cárdenas-Navarro
mesh_terms: D000465:Algorithms; D003433:Crosses, Genetic; D031985:Fragaria / Q000254:growth & development* / Q000378:metabolism* / Q000382:microbiology; D005856:Germ-Free Life; D055137:Glomeromycota / Q000254:growth & development / Q000378:metabolism*; D008800:Mexico; D038821:Mycorrhizae / Q000254:growth & development / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism; D058458:Nitrogen Cycle; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development* / Q000378:metabolism* / Q000382:microbiology; D012987:Soil / Q000737:chemistry
chemical_list: D012987:Soil; D009584:Nitrogen