Arbuscular mycorrhizal fungi and phosphorus in the initial development of Mimosa tenuiflora (Willd.) Poir

The Brazilian Caatinga belongs to the dry forests biome and is threatened due to the conversion of natural areas for anthropogenic uses. An alternative for the recovery of these areas is to plant generalist seedlings, which when inoculated with arbuscular mycorrhizal fungi (AMF), can accelerate the process of ecological succession. The objective of this study was to evaluate the responsiveness of Mimosa tenuiflora (Willd.) Poir. to inoculation with AMF at different doses of phosphorus (P) fertilization. The experiment was completely randomized in a factorial arrangement with three inoculation treatments (noninoculated and inoculated with Claroideoglomus etunicatum, C. Walker & A. Schüssler, emend. Oehl, Sieverd., B. T. Goto & G. A. Silva or Fuscutata heterogama, Oehl, F. A. Souza, L. C. Maia & Sieverd), four doses of single superphosphate (SSP) (0, 22, 66, and 155 mg L−1) in seven replicates. The following parameters were evaluated: height, stem diameter, above- and below-ground biomass, mycorrhizal colonization, number of glomerospores (NG), and shoot nutrient concentration. In general, mycorrhizal plants had higher average height and stem diameter than non-mycorrhizal plants. There was a growth increment of over 200 % in plants inoculated with C. etunicatum or F. heterogama in the soil without application of SSP. The addition of SSP reduced root colonization by the isolates of AMF applied. For the NG, it was observed that F. heterogama produced more glomerospores in natural soil, with NG decreasing above 100 mg L−1 of P in the soil. Plants of mycorrhizal M. tenuiflora had a higher concentration of nutrients, in particular P, Ca, Cu, and Zn. Therefore, M. tenuiflora is responsive to both the fertilization and the inoculation with AMF.