O objetivo desse trabalho foi estabelecer métodos de regeneração de brotações adventícias e axilares in vitro de mogno. Segmentos de epicótilos foram inoculados em meio MS com 0,25; 0,5 e 1,0 μM de BAP e 0,1; 0,25; 0,5; 1,0 e 1,25 μM de TDZ, ambos com 0,5 μM de ANA, e controle sem regulador. Segmentos foliares foram cultivados em meio MS contendo 0,5; 0,75 ou 1,0 μM de TDZ, sob irradiância de 0,73 μmol.m -2 .s -1 (penumbra); 0,75 μM de TDZ, sob irradiância de 0,73 e 37 μmol.m -2 .s -1 e 1,11; 2,22; 4,44 e 8,88 μM de BAP com 0,1 μM de ANA na penumbra, e em meio controle sem regulador. Para regeneração de brotações adventícias, calos de epicótilos cultivados em meio MS com 1,0 μM de TDZ foram transferidos para o mesmo meio com 1,11; 2,22; 4,44 ou 8,88 μM de BAP na penumbra e controle sem regulador. Foram avaliadas porcentagem de formação, oxidação, consistência e coloração dos calos e formação de brotações adventícias. Calos de diferentes consistências e colorações foram obtidos. Os calos de epicótilos cultivados na presença de 1,0 μM de BAP eram compactos (76,4%) e, com 1,0 μM de TDZ, friáveis (91,5%). Em explantes foliares, os melhores resultados de calogênese foram obtidos com 0,75 μM de TDZ na penumbra, onde 90% dos explantes formaram calos e 77,8% eram friáveis. Com 4,44 μM de BAP e 0,1 μM de ANA, a porcentagem de explantes formando calos foi de 93,3%, todos friáveis. Houve formação de 3,33% de gemas adventícias no meio contendo 2,22 μM de BAP. Para multiplicação de gemas axilares, foram utilizados segmentos nodais de plântulas germinadas in vitro, inoculados em meio MS contendo 2,5 μM de BAP combinada com várias concentrações de CIN (0,25; 0,50; 1,0; 1,5 e 2,0 μM) e controle sem regulador. Em outro experimento, foram utilizados meios MS e SH com 2,5 μM de BAP e 2,2 μM de 2-iP com diferentes concentrações de CaCl 2 (MS: 220, 440 e 880 mg.L -1 , SH: 100, 200 e 400 mg.L -1 ) e um tratamento sem CaCl 2 . Foram avaliados número, massa fresca e porcentagem de oxidação dos brotos. No primeiro experimento, nos meios contendo várias concentrações de CIN combinada a BAP, houve intensa oxidação em 90% dos explantes e 10% formaram brotações pouco vigorosas, impossibilitando o subcultivo. No experimento com os meios MS e SH, houve diferenças significativas para o número de brotos, massa fresca das brotações e número de folhas. Sintomas de clorose foliar foram observados nas maiores concentrações de CaCl 2 . Em conclusão, intensa calogênese foi obtida em ambos os tipos de explantes, na presença de difeentes concentrações de TDZ ou BAP, combinadas ou não com ANA; a regeneração de gemas adventícias foi muito baixa. Houve a formação de calos somente na penumbra. Apesar do elevado número de brotos axilares obtidos nos tratamentos com CaCl 2 , estes, quando subcultivados em mesmo meio de origem, sofreram intensa oxidação, impossibilitando o subcultivo. Portanto, não foi possível estabelecer um método eficiente de multiplicação de brotações axilares.
The aim of this work was to establish methods of adventitious and axillary shoot regeneration for mahogany. Epicotyl fragments were inoculated in MS medium supplemented with 0, 0.25, 0.5 and 1.0 μM BAP and 0.1, 0.25, 0.5, 1.0 and 1.25 μM TDZ, both along with 0.5 μM NAA and a control without growth regulators. Leaves were cultivated in MS medium with 0, 0.5, 0.75 and 1.0 μM TDZ under an irradiance of 0.73 μmol m -2 .s- 1 , 0.75 μM TDZ under an irradiance of 0.73 and 37 μmol m -2 .s- 1 and 0, 1.11, 2.22, 4.44 and 8.88 μM BAP with 0.1 μM NAA under an irradiance of 0,73 μmol m -2 .s- 1 . In order to regenerate adventitious shoots, callus originated from epicotyl explants, initially cultivated in 1.0 μM TDZ, were transferred to medium supplemented with 0, 1.11, 2.22, 4.44 and 8.88 μM BAP. Incidence of callus, its consistency and color, and also the number of adventitious shoots formed were recorded after 30 days of culture. In the experiments of axillary shoot formation, the number of shoots, their weight, levels of oxidation and contamination were evaluated. In all experiments, except in shoot regeneration, statistically significant differences were reached. Different consistencies and colors of callus were reached. Most of the calluses from epicotyl segments cultivated with 1.0 μM BAP were compact (76.4%) and with 1.0 μM TDZ most of them were friable (91.5%). The best results were obtained with 0.75 μM TDZ under low light irradiance, 90% of production of callus, of which 77.8% were friable. With 4.44 μM BAP and 0.1 μM NAA the percentage of friable callus was 93.3%. Two adventitious buds were obtained (3.33%) with 2.22 μM BAP. For induction of axillary shoots, nodal segments from in vitro cultivated plants were inoculated in MS medium with 2.5 μM BAP combined with the following concentrations of KIN: 0.25, 0.50, 1.0, 1.5 and 2.0 μM. In another experiment, MS and SH media were used with 2.5 μM BAP and 2.2 μM 2-iP with modification of CaCl 2 concentrations: 0, 0.5x, 1x and 2x that of normal medium concentrations. In the first experiment with several concentrations of KIN in combination with BAP there was an intense oxidation in 90% of the explants. Only 10% of them produced weak shoots which did not permit any subculture. In the experiment with MS and SH media, when CaCl 2 was twice the normal concentration, there was a higher number of shoots (6.8 in SH and 7.8 in MS) and higher weight of shoots (1.27g in SH and 1.63g in MS) than in the other concentrations. When shoots were subcultured in the same media they suffered intense oxidation that did not allow their subculture. In conclusion, callogenesis was reached in both kinds of explants in some TDZ or BAP concentrations, combined or not with ANA. Calluses were formed only in the shadow. Leaf chlorosis symptoms were observed in high concentrations of CaCl 2 . Despite the great number of axillary shoots obtained in CaCl 2 treatments, when they were subcultured in the same medium they suffered intense oxidation that did not allow their subculture. Thus it was impossible to establish an efficient method of axillary shoot multiplication.
