Dependency and Response of Apuleia leiocarpa to Inoculation with Different Species of Arbuscular Mycorrhizal Fungi

Inoculation with arbuscular mycorrhizal fungi (AMF) is a strategy to improve the efficiency of forest plantations, reducing costs and increasing the survival of plant species. The objective of this study was to assess the response and mycorrhizal dependency of seedlings of the forest species Apuleia leiocarpa (Vogel) J.F. Macbr to inoculation with AMF. The experiment was conducted in a completely randomized design using a 5 × 5 factorial arrangement with six replications. The treatments consisted of combinations of five P rates (0, 24, 71, 213, and 650 mg kg-1) with five types of inoculations with AMF (inoculation with the fungi Rhizophagus clarus, Gigaspora margarita, Dentiscutata heterogama, inoculation with an AMF mix of these three species, and a treatment without inoculation). The A. leiocarpa showed the highest biomass accumulations in inoculation with D. hetorogama combined with the P rates of 213 and 650 mg kg-1, and in the AMF mix combined with the P rates of 71, 213, and 650 kg-1. Biomass accumulation showed a linear, positive response to inoculation with D. heterogama combined with the different P rates, and a positive square root fit to inoculation with the AMF mix. The plants inoculated with G. margarita had no significant biomass accumulation. The plant species had a positive response to inoculation with R. clarus combined with the lowest P rates; however, it had a negative response to combination with the highest P rate (650 mg kg-1). The relative benefit of inoculation with these fungi was more than 100 % in most treatments, showing the high mycorrhizal dependency of A. leiocarpa and the nutritional benefit of AMF inoculation for this species. However, this response is dependent on the fungus species that colonize the plant roots. The best combination between fungus and P rate was inoculation with the AMF mix combined with the P rate of 71 mg kg-1.