The Amazon banana plant is of great socio-economical importance, despite its requirement for high agricultural input in order to obtain good yields. An association with arbuscular mycorrhizae fungi could minimize the crop's nutritional needs in the poor soils of the Amazon. The present study aimed at verifying how the plant-fungus mycorrhizal symbiosis influences nutrient concentration in five varieties of adult banana plants cultivated in an acid Amazon Oxisol under field conditions. The banana plantation was defficient in macro (Ca, Mg and P) and micronutrients (Fe, Mn, Zn and Cu). The mycorrhizae colonization varied from 33.6 to 66.5 % of the sampled roots. The average mycorrhizae colonization was 54.9 % in the Mysore, 51.5 % in Maçã, 47.6 % in Pacovan, 47.3 % in Nanica, and 44.7 % in Prata varietes, and they were significantly different from each other. The mycorrhizae colonization indexes of Mysore and Maçã varieties were highest in January and August and those of Nanica peaked in July, January and August. Pacovan and Prata did not present significant variations of mycorrhizae colonization during the studied period. The mycorrhizae association was significantly correlated with the leaf concentration of K, Mg, P, and Zn in the Maçã variety, of K and P in Nanica, and of Zn in Prata variety.
mycorrhizal fungi; Musa spp; mineral nutrition
