Histodifferentiation of oil palm somatic embryo development at low auxin concentration.

Large-scale propagation of oil palm (Elaeis guineensis, Jacq.) is difficult due to its single apical meristem. Thus, obtaining plants is mainly through seed germination, and a long growing period is required before oil production is possible. An alternative to large-scale seedling production is indirect somatic embryogenesis. The aim of this study was to analyze the somatic embryogenesis process in oil palm (E. guineensis Jacq.) with amino acids and low concentrations of auxins. The Tenera hybrid was analyzed by cytochemical and ultrastructural methods and was used to regenerate oil palm plants. First, calli were induced in MS culture media supplemented with 2,4-D and picloram. Two types of calli were obtained, characterized by beige or translucent color. Beige calli had embryogenic characteristics, such as large nuclei with prominent nucleoli, and they were multiplied for 8 months in MM culture (half strength MS, 1 mg L-1 2,4-D, 2 mg L-1 2iP, 1 mg L-1 IBA, 250 mg L-1 citric acid, 10 mg L-1 cysteine, 100 mg L-1 inositol, 1 mg L-1 thiamine, 1 mg L-1 pyridoxine, 1 mg L-1 nicotinic acid, 1 mg L-1 glycine, 200 mg L-1 malt extract, and 100 mg L-1 casein hydrolysate). After multiplication, the MCB culture medium (half strength MS, supplemented with 0.25 mg L-1 NAA, 2 mg L-1 BAP, MM vitamins and 200 mg L-1 malt extract, and 100 mg L-1 casein hydrolysate) was the most efficient for embryo formation, showing meristematic centers with totipotent cells in histochemical analyses. The somatic embryos were developed and germinated in MG medium (half strength MS, 0.45 mg L-1 IAA, 0.25 mg L-1 BAP, and MM vitamins), transplanted into polyethylene tubes containing pine bark substrates, and acclimatized in a greenhouse, achieving a 97% survival rate. The use of picloram for callus induction and somatic embryogenesis is advantageous and multiplication in MM medium is an important step for increasing cell mass. The calli with light beige color and nodular structures have meristematic cells with dense cytoplasm and totipotential features that later give rise to protoderm, procambium, and ground meristem during the globular, cordiform, and torpedo embryogenesis phases. In MCB medium, the concentration of vitamins and amino acids are crucial for somatic embryogenesis.

Assessment of antimicrobial activity in vitro of ethanolic extracts of Banisteriopsis anisandra (A. Juss. ) B. Gates (Malpighiaceae) / Avaliação da atividade antimicrobiana in vitro de extratos etanólicos de Banisteriopsis anisandra (A. Juss. ) B. Gates (Malpighiaceae)

The aim of this study was to evaluate the antimicrobial activity in vitro of ethanolic extracts of Banisteriopsis anisandra. Tests were performed using the extracts overlay method in the culture medium for phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum, and disk diffusion for the microorganisms Staphylococcus aureus and Candida albicans. Ethanolic extracts from leaves were prepared by maceration (extract I) and decoction (extract II) at 430.0, 215.0 and 107.5 mg/mL. The growth inhibition of R. solani and F. oxysporum was determined by calculating the mycelia growth speed rate (MGSR) and, in relation C. albicans and S. aureus, it was determined by measuring the inhibition halos. Extracts that caused significant inhibition were also tested at 86.0, 64.5, 43.0 and 21.5 mg/mL for C. albicans and S. aureus. Both extracts showed inhibitory activity on the microorganisms studied. Rizoctonia solani showed lower MGSR in the presence of extract II (107.5 mg/mL) and Fusarium oxysporum showed slight MGSR reduction in the presence of extract I (107.5 mg/mL) and II (107.5 and 215 mg/mL). Ethanolic extracts I and II inhibited the growth of C. albicans, with the highest rates of inhibition observed in the presence of extract II (215.0 mg/mL). For S. aureus, the highest inhibitory activity was observed in the presence of ethanolic extract II, prepared by decoction at 430.0 mg/mL. Results showed a promising antimicrobial activity of extracts of B. anisandra, which may contribute to further studies leading to a future development of medicines to treat human and plant diseases caused by these organisms.

O objetivo deste estudo foi avaliar a atividade antimicrobiana in vitro de extratos etanólicos de Banisteriopsis anisandra. Os testes foram realizados utilizando o método de sobreposição de extratos em meio de cultura para fungos fitopatogênicos Rhizoctonia solani e Fusarium oxysporum e de difusão em disco para os microrganismos Staphylococcus aureus e Candida albicans. Foram testados de extratos etanólicos de folhas preparados por maceração (extrato I) e decocção (extrato II), nas concentrações de 430,0; 215,0 e 107,5 mg/mL. A inibição do crescimento de R. solani e F. oxysporum foi determinada pelo cálculo do índice de velocidade de crescimento micelial (IVCM) e de C. albicans e S. aureus, por meio da medida da halos de inibição. Os extratos que causaram inibição significativa também foram testados nas concentrações de 86,0; 64,5; 43,0 e 21,5 mg/mL para C. albicans e S. aureus. Ambos os extratos mostraram atividade inibitória sobre os microrganismos estudados. Rizoctonia solani apresentou menor IVCM na presença do extrato II (107,5 mg/mL) e Fusarium oxysporum apresentou discreta redução no IVCM na presença do extrato I (107,5 mg/mL) e II (107,5 e 215 mg/mL). Extratos etanólicos I e II inibiram o crescimento de C. albicans, com as maiores taxas de inibição observadas na presença do extrato II (215,0 mg/mL). Para S. aureus a maior atividade inibitória foi observada na presença do extrato II, na concentração de 430 mg/mL. Os resultados mostraram promissora atividade antimicrobiana de extratos de B. anisandra, o que pode contribuir para estudos futuros visando o desenvolvimento de medicamentos para doenças humanas e de plantas causadas por estes microrganismos.