ABSTRACT This work describes the establishment of procedures to induce in vitro callogenesis from Poincianella pyramidalis (Tul.) L. P. Queiroz, Fabaceae, explants. Nodal, internodal and leaf segments were isolated from in vitro germinated seedlings and cultured in MS medium with 0, 2.5, 5 and 10 mg l-1 of 2,4-dichlorophenoxyacetic acid. After 30 days, the explants with induced callus showed a quadratic response for the segments nodal, internodal and leaf, with increasing the callus formation in 2,4-dichlorophenoxyacetic acid concentrations of 6.28, 6.49 and 4.91 mg l-1, respectively. In 30 days there was a linear oxidation rise with the increase to the 2,4-dichlorophenoxyacetic acid. After 60 days, oxidation values were minimum, at 2,4-dichlorophenoxyacetic acid concentrations of 5.13 mg l-1 (internodal) and 3.98 mg l-1 (leaf). The highest callus production was observed after 30 days in the presence of 6.09 mg l-1, 5.82 mg l-1 and 4.91 mg l-1 of 2,4-dichlorophenoxyacetic acid in nodal, internodal and leaf segments, respectively. After 60 days these segments showed peaks of production at 7.0 mg l-1 (nodal), 6.15 mg l-1 (internodal) and 5.08 mg l-1 (leaf) of 2,4-dichlorophenoxyacetic acid. For callus induction the intake of 2,4-dichlorophenoxyacetic acid was essential. The greater intensity in callus formation was observed in 4.91 mg l-1 in leaf segments after 30 days.

Foram realizados dois experimentos com o objetivo de estudar os efeitos de fontes de nitrogênio, polpa de banana e ágar no desenvolvimento in vitro de orquídea Cattleya loddigesii. O primeiro experimento constituiu-se de NH4NO3 (0; 25; 50; 75 e 100% da formulação de 330 mg L-1) e KNO3 (0; 25; 50 e 100% da formulação de 380 mg L-1) acrescidas ao meio MS. No segundo experimento, os tratamentos consistiram de concentrações de ágar (0; 2; 4; 6 e 8 g L-1), no meio de cultura Knudson C, acrescido de polpa de banana nanica (0; 50; 100; 150 e 200 g L-1) em todas as combinações possíveis. Após a inoculação as culturas foram mantidas em sala de crescimento com irradiância em torno de 35 μmol m-2 s-1, temperatura de 25±1ºC e fotoperíodo de 16 horas, por 90 dias. Com base no peso da matéria fresca das plântulas, número de raízes, comprimento da parte aérea e comprimento da maior raiz, a adição de 17,5 a 41,16% da formulação original de NH4NO3 ao meio MS proporcionou melhor desenvolvimento in vitro em plântulas de Cattleya loddigesii. Maior número de folhas foi obtido com a adição ao meio MS de 100% da formulação original de NH4NO3 e 50% de KNO3. A multiplicação in vitro de plântulas de orquídea Cattleya loddigesii é viável em meio Knudson C líquido com a utilização de 128,42 g L-1 de polpa de banana nanica.

Two experiments were carried out in order to evaluate the effects of nitrogen sources, banana pulp and agar on Cattleya loddigesii seedlings development in vitro. In the first experiment were tested NH4NO3 at 0; 25; 50; 75 and 100% (330 mg L-1 formulation) and KNO3 0; 25; 50 and 100% (380 mg L-1 formulation) added to MS medium. The second experiment consisted of different agar concentrations (0; 2; 4; 6 and 8 g L-1), banana nanica pulp (0; 50; 100; 150 and 200 g L-1) in all the possible combinations added to Knudson C medium. After inoculation the plantlets were maintained in growth room with irradiancy around 35 μmol m-2 s-1, 25±1ºC temperature and 16-hour photoperiod for 90 days. The NH4NO3 formulation added to culture medium at 17,5 to 41,16% provides best development of Cattleya loddigesii plantlets based on plantlets fresh mass, number of roots, largest root length and aerial part length. Larger number of leaves was obtained at 100% of the original formulation of NH4NO3 and 50% of KNO3 in MS medium. The best results for in vitro multiplication of Cattleya loddigesii orchid seedlings occurred in liquid Knudson C medium with 128,42 g L-1 banana nanica pulp.