EFFECT OF ARBUSCULAR MYCORRHIZAL FUNGI AND PHOSPHATE FERTILIZATION ON INITIAL GROWTH OF SIX ARBOREAL SPECIES OF CERRADO

This study evaluated the benefit of inoculation with arbuscular mycorrhizal fungi, Glomus clarum, for the initial growth of some native arboreal species of the Cerrado biome, namely gabiroba (Campomanesia cambessedeana), baru (Dipterix alata), jatoba (Hymenaea courbaril), inga (Inga laurina), caroba (Jacaranda cuspidifolia) and chicha, (Sterculia striata), in unsterilized soil with low (0.02 mg L-1) and high (0.2 mg L-1) concentrations of P in the soil solution. Experiments were conducted in a greenhouse, using 1.5 kg vases, for up to 120 days. The experimental design for each arboreal species was completely randomized, with ten replicates in a 2x2 factorial design (inoculated and noninoculated seedlings, and two levels of phosphorus (P) in the soil solution). Arboreal plants of the Cerrado biome showed increased mycorrhizal colonization from inoculation with Glomus clarum, except chicha, as this species showed a high indigenous colonization, not differing from the colonization promoted by inoculated fungi. Inoculation promoted increased growth in baru, gabiroba, inga, caroba and chicha, increasing shoot thy matter (MSPA) and root dry matter (MSR). In caroba, this effect was synergistic with application of P to the soil. Baru and jatoba showed increased thy matter with application of P to the soil only. The mycotrophy (mycorrhizal dependence) of species and their response to inoculation and to phosphorus are discussed. In order to produce quality seedlings of caroba, gabiroba, chicha and inga, combining inoculation with Glomus clarum and phosphate fertilization of the soil is recommended, while for jatoba and baru only the application of P to the soil is recommended.