Multiplication and in vitro rooting of Handroanthus impetiginosus Mattos

This study aimed to evaluate cytokinin influence during in vitro multiplication stage and activated charcoal in combination with indole-3-butyric acid (IBA) during in vitro rooting of Handroanthus impetiginosus. For in vitro multiplication, nodal segments of shoots obtained from in vitro seedlings establishment were inoculated in Woody Plant Medium (WPM), with and without the following concentrations of 6-benzylaminopurine (BAP), kinetin (KIN) and thidiazuron (TDZ): 0.5; 1.0; 2.0; 4.0 and 8.0 [micro]mol [L.sup.-1]. For in vitro rooting, shoots were inoculated in WPM containing combinations among IBA (1.0; 3.0; 6.0 and 9.0 [micro]mol [L.sup.-1]) and activated charcoal (1.0; 2.0 and 3.0 g [L.sup.-1]), as well as their absence within culture medium. The highest number of shoots and buds was reached after using TDZ 8.0 [micro]mol [L.sup.-1], where in the best rooting occurred after adding activated charcoal 2.0 g [L.sup.-1], regardless of IBA concentration. Our results show that using TDZ in a suitable level for in vitro multiplication stage followed by using 2.0 g [L.sup.-1] of activated charcoal to obtain well rooted shoots is efficient for ipê-roxo micropropagation in a low cost-manner and quickly, besides providing knowledge about how to keep this threatened extinction species in an in vitro environment, which may help other conservation studies. Keywords: In vitro propagation; Woody plant; Plant tissue culture; Ipê-roxo Este estudo objetivou avaliar a influência das citocininas durante o estágio de multiplicação in vitro e a combinação entre carvão ativado com o ácido indol-3-butírico (AIB) durante o enraizamento in vitro de Handroanthus impetiginosus. Para a multiplicação in vitro, os segmentos nodais dos brotos obtidos a partir do estabelecimento de plântulas in vitro foram inoculados em meio de cultura Woody Plant Medium (WPM), com e sem as seguintes concentrações de 6-benzilaminopurina (BAP), cinetina (KIN) e tidiazuron (TDZ): 0,5; 1,0; 2,0; 4,0 e 8,0 [micro]mol [L.sup.-1]. Para o enraizamento in vitro, brotos foram inoculados em meio WPM contendo combinações entre AIB (1,0; 3,0; 6,0 e 9,0 [micro]mol [L.sup.-1]) e carvão ativado (1,0; 2,0 e 3,0 g [L.sup.-1]), bem como suas ausências no meio de cultura. O maior número de brotos e gemas foi alcançado após usar 8,0 [micro]mol [L.sup.-1] de TDZ, enquanto que o melhor enraizamento ocorreu após a adição de 2,0 g [L.sup.-1] de carvão ativado, independente da concentração de AIB. Nossos resultados mostram que