Poincianella pyramidalis (Tul.) L.P. Queiroz, is an arboreal species endemic to Brazil’s Caatinga biome and an important source of lumber and also of medicinal substances. This study aimed to evaluate the effect of the osmotic agents sucrose, sorbitol and mannitol and the growth retardant paclobutrazol (PBZ) on the induction of slow growth in vitro of P. pyramidalis, seeking to establish alternative techniques for ex situ conservation of the species. In the first experiment, plantlets with seven days of age were inoculated on Woody Plant Medium (WPM) supplemented with four concentrations of sucrose (87.64, 131.46, 175.28 or 219.10 mM) combined with 0.0 or 87.64 mM sorbitol or mannitol. In the second experiment, these plantlets were inoculated on WPM medium with 0.0, 1.5, 3.0, 4.5 or 6.0 µM PBZ and supplemented with 87.64 mM sucrose. For both experiments, the survival percentage of the plants was evaluated every 60 days, and at the end of 240 days, the following parameters were recorded: number of green leaves and senescent leaves; length of the aerial part and longest root; and dry mass of the aerial part and roots. The best results to maintain the quality of the P. pyramidalis plants conserved in vitro were obtained on medium supplemented with 219.10 mM sucrose for up to 240 days without subculture. With respect to PBZ, the concentration of 6.0 μM can be recommended for in vitro conservation of P. pyramidalis for 240 days without the need of subculturing.

Resumo -Caesalpinia pyramidalis é uma espécie endêmica da Caatinga, conhecida popularmente como catingueira, que possui ampla utilização pelas populações locais, principalmente por suas propriedades madeireiras, medicinais e forrageiras. Este trabalho objetivou estudar os efeitos dos tipos e concentrações de reguladores de crescimento vegetal sobre a multiplicação in vitro de C. pyramidalis. No primeiro experimento, segmentos nodais foram inoculados em meio contendo diferentes combinações (0,0-8,0 µM) de BAP e de ANA. No segundo experimento, segmentos nodais foram inoculados em meio contendo diferentes tipos (KIN, BAP e TDZ) e diferentes concentrações (0,0-16 µM) de citocininas. Utilizou-se o meio de cultura WPM suplementado com 87,64 mM de sacarose e solidificado com 7,0 g L -1 de ágar. Após 45 dias registrou-se o maior número de brotos, número de folhas, comprimento da parte aérea e matéria seca da parte aérea em meio de cultura isento de regulador de crescimento vegetal. Palavras-chave adicionais: cultivo in vitro, organogênese, reguladores de crescimento vegetal.Abstract (In vitro multiplication of Caesalpinia pyramidalis (Leguminosae)) -Caesalpinia pyramidalis is a species endemic to the Caatinga and known popularly as catingueira, which is widely used by local people, mainly for its timber and medicinal and fodder properties. This study investigated the effects of different types and concentrations of plant growth regulators on the in vitro multiplication of C. pyramidalis.In the first experiment, nodal segments were inoculated in media containing different combinations (0.0-8.0 µM) of BAP and NAA. In the second experiment, nodal segments were inoculated in media containing different types (KIN, BAP and TDZ) and concentrations (0.0-16μM) of cytokinins. We used a WPM medium supplemented with 87.64 mM sucrose and solidified with 7.0 g L -1 agar. After 45 days, the highest number of shoots, leaf number, shoot length and dry mass of shoots were obtained when nodal segments were inoculated into a culture medium without plant growth regulators. Additional key words: in vitro culture, organogenesis, plant growth regulators.

In vitro multiplication of Tapirira guianensis Aubl. (Anacardiaceae)Tapirira guianensis is of great medicinal, ecological and socio-economical importance occurring throughout the Brazilian territory. The objective of this study was to establish and determine the best conditions for the in vitro multiplication of T. guianensis. The explants nodal, cotyledonary and epicotyl segments from seedlings germinated in vitro were tested in diverse concentrations of 6-benzilaminopurine (BAP) and/or napthaleneacetic acid (NAA) in medium WPM. The following parameters were evaluated: the percentage of responsive explants, the number of shoots and buds, and the length of shoots and shoot dry mass at 30 and 60 days after inoculation. The cotyledonary segment, under these conditions, is the most suitable explant for the multiplication, with no induction of adventitious buds in epicotyl. The treatment with 1.0 mg L -1 BAP in the absence of NAA is the most responsive to the T. guianensis regeneration.Key words: medicinal woody, in vitro propagation, regeneration, direct organogenesis. Tapirira guianensis possui grande relevância medicinal, ecológica e socioeconômica, ocorrendo em todo o territó-rio brasileiro. O objetivo deste estudo foi estabelecer e determinar as melhores condições para a sua multiplicação in vitro. Os explantes, segmentos nodais, cotiledonares e epicótilos, oriundos de plântulas germinadas in vitro, foram testados em concentrações de 6-benzilaminopurina (BAP) e, ou, ácido naftalenoacético (ANA), em meio de cultura WPM. As características avaliadas foram a percentagem de explantes responsivos, o número de brotos e de gemas, o comprimento dos brotos e a matéria seca da parte aérea, aos 30 e 60 dias após inoculação. Foi observado que o segmento cotiledonar, nas condições deste estudo, foi o explante mais indicado para a multiplicação, não havendo indução de brotos adventícios nos epicótilos. O tratamento com 1,0 mg L -1 de BAP na ausência de ANA é o mais responsivo para a regeneração de T. guianensis.Palavras-chave: lenhosa medicinal, propagação in vitro, regeneração, organogênese direta.