In vitro conservation of mangaba (Hancornia speciosa Gomes): an important fruit tree of Brazilian cerrado

Abstract

This study aimed at evaluating the effect of osmotic agents, sucrose, and abscisic acid on the in vitro conservation of mangaba trees by slow growth. Two experiments were carried out. Nodal segments were inoculated in the MS medium with the addition of 1) osmotic agents (15, 20, and 25 g L-1 of mannitol and 10, 20, and 40 g L-1 of sorbitol) + control; 2) sucrose (0, 10, 20 and 30 g L-1) and abscisic acid – ABA (0 and 0.5 mg L-1). After carrying out the experiments, both were performed again, this time with the addition of 2 g L-1 activated charcoal to the medium for comparison. The survival rate and number of green leaves were evaluated after 45 and 90 days. For growth recovery, the explants were transferred to a specific growth medium, consisting of MS medium supplemented with 7 g L-1 agar, 1 mg L-1 6-benzylaminopurine (BAP), 1 mg L-1 1-naphthaleneacetic acid (NAA), 2 g L-1 activated charcoal. At 60 days, survival rate, number of green leaves, number of nodes, shoot length and fresh weight of the explants were assessed. The results showed that the use of 2 g L-1 of activated charcoal improves the growth and development of the explants. The tested doses of osmotic agents also did not influence the evaluated characteristics. However, there was significant effect of osmotic agent and time on survival rate and treatment x time interaction for the number of green leaves, having been influenced also by the use of osmotic agent at 45 days, in addition to significant differences between the control and the other treatments for this characteristic. The osmotic agents were not effective in plant conservation as well as the use of ABA. According to the conditions of this study, it is recommended the use of 30 g L-1 sucrose to the culture medium for up to 90 days in a row of in vitro conservation of mangaba plants.