Micropropagation of Apeiba tibourbou Aubl (Tiliaceae), a multipurpose species with wide distribution in forests of Brazil

Apeiba tibourbou is a common species found in the rainforests of South America. The aim of the present work is to determine the most favorable condition for micropropagation. Seeds were submitted to both thermal and mechanical scarification, sterilized and inoculated in test tubes with 1⁄2 MS, with or without the addition of sucrose. The explants were divided in a factorial experiment of four concentrations (0; 0.1; 0.5 and 1.0 mgL) of 6benzylaminopurine (BAP) and three auxins at the concentration of 0.01 mg.L: indole-3-acetic acid (AIA), indole-3-butyric acid (AIB) or naphthalene-acetic acid (ANA). Regarding the production of new sprouts, auxins had an inhibitory effect on sprouting, and the best results were obtained with BAP at the concentration of 0.5 mgL without auxins or with AIA. However, regardless the culture medium the sprouts died in the following subculture. All the explants cultivated in the absence of growth regulators rooted. All combinations of growth regulators inhibited the formation of roots, except in the presence of AIA alone. The multiplication using sprouts formed in vitro remain a challenge to overcome.