RESUMOO objetivo do trabalho foi determinar as condições mais favoráveis para a germinação in vitro de sementes e o crescimento inicial de plântulas de mangabeira. Após assepsia, sementes oriundas de frutos maduros foram inoculadas em tubos de ensaio contendo os seguintes tratamentos: T1-15 mL de meio de cultura MS; T2-15 mL de meio de cultura MS + 2,0 g L -1 de carvão ativado; T3-15 mL de meio de cultura ½ MS; e T4-15 mL de meio de cultura ½ MS + 2,0 g L -1 de carvão ativado. Todos os meios de cultura foram gelificados com 0,3 g L -1 de Phytagel® e suplementados com 3,0 g L -1 de sacarose. O experimento foi instalado em delineamento inteiramente casualizado com quatro tratamentos e oito repetições, sendo cada parcela experimental composta de dez tubos de ensaio contendo uma semente cada. Não houve diferença significativa dos tratamentos para a porcentagem de germinação aos 20 dias, que variou de 95 a 100%. Quanto ao comprimento da raiz principal, observou-se que o meio de cultura constituído de ½ MS com 2,0 g L -1 de carvão ativado proporcionou maior crescimento quando comparado com os demais tratamentos. Aos 50 dias, não foi observada a formação de plântulas anormais e nem diferenças significativas do comprimento da parte aérea das plântulas. Entretanto, a diluição em 50% dos sais do meio MS associada à presença de carvão ativado induziu maior crescimento da raiz principal (8,50 cm) quando comparado com meio MS, na presença (6,19 cm) ou ausência (6,00 cm) de carvão ativado. Termos para indexação:Propagação in vitro, meio de cultura, sementes, Apocynaceae. ABSTRACTThe objective of this study was to determine the most favorable conditions for the in vitro germination of mangaba seeds and initial development of plantlets. After asepsis, emerging seeds of mature fruits were inoculated in tubes contend the next treatments: T1-15 mL of MS culture medium; T2-15 mL of MS culture medium + 2.0 g L-1 of activated charcoal; T3-15 mL of ½ MS culture medium; and T4-15 mL of ½ MS culture medium + 2.0 g L-1 of activated charcoal. All the culture medium were gellified with 0.3 g L-1 of Phytagel® and supplemented with 3.0 g L-1 of sucrose. The statistical design was completely randomized with four treatments, eight repetitions and ten seeds by experimental unit. There was not significant difference of the treatments for the germination percentage at twenty days, which varied from 95 to 100%. The ½ MS with 2.0 g L-1 of activated charcoal promoted higher growth the main root when compared with the others treatments. After 50 days, abnormal plantlets were not observed and neither significant difference were verified among the length of the aerial part. However, the dilution in 50% of the MS culture medium associate to the presence of activated charcoal induced higher growth of the main root (8.50 cm) when compared with MS culture medium in the presence (6.19 cm) or absence (6.00 cm) of activated charcoal.

Dendrocalamus asper is a thick-walled bamboo species widely used for edible shoots, chop sticks, rural housing, structural and building construction, ornamental and ecotourism purposes in Malaysia. However, due to the declination of timber production, increasing human population and their ever increasing demand, natural bamboo stands will not be able to cope with the growing demand in the future. Supply of bamboo may be increased through large-scale commercial or industrial plantations to fulfil the gap between demand and supply. However, the main problem for commercial plantation of bamboo species in Malaysia is the inadequate supply of quality planting materials since most of the commercially important bamboo species do not produce or produce few seeds after long intervals. The current study was therefore, designed to investigate the mass propagation potential of D. asper through branch cutting using an easy, inexpensive and efficient method. Primary or secondary branches consisting of three to four nodes along with the swollen base were planted into plastic buckets filled with coarse sand in partial shade under nursery condition. Before planting the cuttings, bases were treated with 0, 0.2, 0.4 or 0.8% indole-3-butyric acid (exogenous IBA) solution for 5 min. The species was found to develop root, shoot and rhizome even without any rooting hormone. However, rooting ability, shoot number and length and survival percentage were significantly enhanced when cuttings were treated with IBA. Findings of the present study are expected to have significant impact on vegetative propagation of this thick-walled bamboo species.