Conservação in vitro de mangabeira da região Nordeste do Brasil

Abstract

The mangaba tree (Hancornia speciosa Gomes) is a species whose natural occurrence has suffered great human pressure, which is causing genetic erosion in many populations, especially in the Northeast Brazil. Due to the existence of few collections of mangaba tree preserved ex situ, it's important to develop a complementary and alternative method to germplasm conservation of this species. The use of techniques of plant tissue culture for conservation of plant genetic resources presents several advantages over germplasm conservation in the field, especially when focusing cost reduction for the maintenance of collections, sanitary risk and weather problems. The present research aimed to evaluate the effectiveness of regulators osmotic mannitol and the growth inhibitor abscisic acid on the in vitro conservation of mangaba microcutting under slow growth. The cultures were maintained in MS medium with 3% sucrose and 0.6% of agar. The experiments were conducted in a randomized blocks design in a growth room with temperature ranging from 26±2°C, average relative humidity around 70% and photoperiod of 12 hours of cold white light (52μmol m-2 s-1 irradiance). It was evaluated five concentrations of mannitol (0, 10, 15 and 20g L-1). Mannitol in the presence of the length of shoots showed values below the control, but after 90 days of in vitro culture was observed deleterious effect of mannitol in microcutting. It was tested five concentrations of abscisic acid (0; 0.5; 1; 2 and 4mg L-1) in interaction with two types of sealing bottles (plastic cover and threaded aluminum foil) and two types of explants (apical and basal microcutting). Abscisic acid (0.5mg L-1) showed better results for in vitro conservation of seedling of mangaba microcutting grown in flasks sealed with aluminum foil. There was no significant effect of explant type.