Resumo O objetivo deste trabalho foi estabelecer um protocolo eficiente para a organogênese in vitro de Dalbergia nigra. Para isso, plântulas com 30 dias de idade foram seccionadas em seus nós cotiledonares e segmentos nodais. Esses materiais foram cultivados em meio com diferentes combinações das citocininas 6-benzilaminopurina e tidiazuron. Após 60 dias em sala de crescimento mantida a 27°C e submetida a fotoperíodo de 16 horas, foram analisadas as características de crescimento. Explantes dos nós cotiledonares apresentam maior potencial morfogenético, independentemente da adição de citocininas. Nós cotiledonares em meio suplementado com 2.22 µmol L-1 de BAP são a melhor combinação para a propagação in vitro de D. nigra.

Abstract The objective of this work was to establish an efficient protocol for the in vitro organogenesis of Dalbergia nigra. For this purpose, 30-day-old seedlings were sectioned at their cotyledonary nodes and nodal segments. These materials were cultivated in a medium with different combinations of the 6-benzylaminopurine and thidiazuron cytokinins. After 60 days in a growth chamber set at 27°C and a 16-hour photoperiod, growth characteristics were analyzed. Explants from the cotyledonary nodes show a greater morphogenetic potential, regardless of the addition of cytokinins. Cotyledonary nodes in the medium supplemented with 2.22 µmol L-1 BAP show the best combination for the in vitro propagation of D. nigra.

ABSTRACT The Atlantic Forest is a biome that has suffered anthropic actions, such as the extraction of hardwood, which can lead to the extinction of endemic species of great economic and ecological value, such as Dalbergia nigra. In this perspective, large-scale multiplication studies are necessary to contribute to the conservation of this species. The objective of this work was to establish a protocol for the in vitro production of axenic seedlings of D. nigra. Four experiments were performed: I. Immersion times in NaOCl. II. Disinfecting agents in seed germination of D. nigra. III. NaOCl toxicity in seeds of the model species Lactuca sativa L. IV. Culture media and glutamine in the germination and initial growth of D. nigra. All experiments were arranged in a completely randomized design. For a better disinfestation and less harmful effects to the seedlings, it is recommended that the seeds be treated with 70% alcohol (1 min) and NaOCl (14 min). NaOCl has a high phytotoxic, cytotoxic, and genotoxic effect, and its mechanism of action in the L. sativa cell cycle is clastogenic and aneugenic, suggesting the formation of abnormal seedlings in D. nigra. The WPM medium and its supplementation with glutamine (0.75 mg.L-1) are recommended.

Resumo: O objetivo deste trabalho foi avaliar a biometria de frutos e sementes e a diversidade de genótipos de sapucaia (Lecythis pisonis). Frutos de 12 genótipos de sapucaia foram coletados de plantas na região norte do Estado do Espírito Santo e leste do Estado de Minas Gerais. Os dados foram submetidos à análise de variância, e as médias dos diferentes genótipos foram comparadas pelo teste de agrupamento de Scott-Knott. A diversidade fenotípica foi analisada por meio da distância de Mahalanobis, e o agrupamento, pelo método de otimização de Tocher e por dispersão gráfica a partir das variáveis canônicas. A contribuição relativa das características para diversidade foi avaliada pelo método de Singh. Os genótipos de sapucaia divergiram quanto às características morfológicas de frutos e sementes. O genótipo 1 produziu o maior número de sementes por fruto, e os genótipos 2 e 7 produziram sementes de maiores dimensões. Esses genótipos foram separados em grupos distintos, o que é indício de sua combinação para uso em programas de melhoramento.

Abstract: The objective of this work was to evaluate the biometry of fruit and seed, and the diversity of paradise nut (Lecythis pisonis) genotypes. Fruit of 12 paradise nut genotypes were collected from plants in the northern region of the state of Espírito Santo and in the eastern region of the state of Minas Gerais, Brazil. Data were subjected to the analysis of variance, and means of the different genotypes were compared by Scott-Knott’s mean clustering test. The phenotypic diversity was analyzed using Mahalanobis’ generalized distance, and clustering, by Tocher’s optimization method and the graphical dispersion of canonical variables. The relative contribution of the characters to diversity was assessed by Singh’s method. The paradise nut genotypes differed regarding the morphological characteristics of fruit and seed. Genotype 1 produced the largest number of seed per fruit, and genotypes 2 and 7 produced the largest seed. These genotypes were clustered into different groups, which is indicative of their potential combination for use in genetic breeding programs.