Inoculum density of arbuscular mycorrhizal fungi needed to promote growth of Hancornia speciosa Gomes seedlings

摘要

Arbuscular Mycorrhizal Fungi (AMF) can promote host growth and among other benefits, alleviate the stress produced by transplanting seedlings from the nursery to the field. The objective of this work was to evaluate the effect of the amount of AMF inoculum on growth of Hancornia speciosa (Mangaba tree). Materials and methods. A greenhouse experiment was performed using a randomized experimental design in a factorial arrangement of 3 X 3 corresponding to: two AMF (Gigaspora alhida schenck & Smith and Gromus etunicatum Becker & Gerdeman) treatments plus one control with plants without AMF X three inoculum densities [(50. 100 and 300) spores per plant], with five replicates, in a methyl bromide sterilized soil, Results. After 120 d. seedlings associated with G. albida had greater height, shoot diameter and dry biomass of the aerial purl and leaf area than those associated with G. tunicatum, independent of inoculum density. G. etunicatum did not influence growth of H. speciosa. Positve correlations occurred between plant growth parameters and root colonization promoted by G. alhida. Regression analysis showed interaction between the inoculum density of G. alhida and plant growth parameters. Discussion and conclusion. Increments in growth of H. speciosa can be obtained with inoculation of approximately 180 spores of G. alhida per plant, which could reduce the necessary period of time for the transplanting of seedlings from the nursery to the field.