GROWTH OF SWEET PASSION FRUIT SEEDLINGS INOCULATED WITH ARBUSCULAR MYCORRHIZAL FUNGI AND DIAZOTROPHIC BACTERIA UNDER DIFFERENT LEVELS OF PHOSPHORUS

An experiment, at greenhouse conditions, was carried out to evaluate the effects of inoculation with mycorrhizal fungi (AMF) and diazotrophic bacteria, on sweet passion fruit seedling growth under different phosphorus levels. The experiment design was randomized blocks in 3x2x4 factorial, with three treatments with fungi: Gigaspora margarita, Glomus clarum and control (without fungus); two treatments with bacteria: Burkholderia sp. + Burkholderia silvatlantica and control (without bacteria); and four P levels: 0, 15, 30 and 60 mg dm(-3) of soil, with four replications. The experimental unit consisted of a 3.5 dm(3) pot with three plants. The seedlings were grown from seed and transplanted to pots containing a sterile soil: sand mixture (1:2 v: v). At 90 days after transplantation were assessed: height, diameter of stem, leaf area, shoot dry weight, percentage of root colonization by fungi and enumeration of diazotrophs in roots. Despite the presence of diazotrophic bacteria, inoculation with AMF provided increase in height, shoot dry weight, leaf area and stem diameter of seedlings, both at 0 and 15 mg dm(-3) of P levels. Bacteria increased height and leaf area in shoots when associated with the AMF species of G. margarita, however in the absence of AMF, they reduced the shoot dry mass, regardless of P levels in the substrate.