Aline Ritter Curti

Estabelecimento e desenvolvimento in vitro de Eugenia involucrata DC.: influência do tipo de explante e do meio nutritivo

Apresentando diversas caracteristicas de interesse nos setores da silvicultura, fruticultura, meio ambiente e medicinal, Eugenia involucrata DC. (Myrtaceae) e uma especie florestal nativa de varios Estados brasileiros. Considerada a dificuldade da propagacao por sementes, que sao recalcitrantes, perdendo rapidamente sua viabilidade apos a colheita, este trabalho objetivou avaliar a influencia do uso de segmentos apicais e nodais cultivados em diferentes meios nutritivos no estabelecimento e no desenvolvimento in vitro desta especie. Segmentos apicais e nodais coletados em plantas de tres anos de idade, mantidas em casa de vegetacao, foram inoculados nos meios nutritivos MS, ½ MS e WPM. Em um primeiro momento, adicionaram-se aos meios de cultura 1 μM de ANA e 5 μM de TDZ e, apos, os explantes foram transferidos para frascos contendo os respectivos meios nutritivos frescos, na ausencia de reguladores de crescimento, mas com o acrescimo de 1 g L-1 de carvao ativado, sendo cultivados por 30 dias adicionais. Os meios ½ MS e WPM sao adequados para o estabelecimento e o desenvolvimento in vitro a partir do cultivo de segmentos nodais, enquanto que, com segmentos apicais, e apropriado o meio ½ MS. O meio ½ MS possibilitou os melhores indices de enraizamento nos explantes, juntamente com o meio WPM. O estabelecimento e o enraizamento in vitro foram promovidos pelo cultivo de segmentos apicais e nodais de Eugenia involucrata DC. Os meios nutritivos ½ MS e WPM sao apropriados para o cultivo in vitro de segmentos nodais de E. involucrata, recomendando-se o meio ½ MS pela economia e praticidade. Para segmentos apicais, o uso do meio de cultura ½ MS e mais adequado que o dos meios MS e WPM.

Substratos alternativos e tratamentos pré-germinativos na germinação in vitro de sementes de Pinus taeda L.

The aims of this paper were to develop protocols to obtain in vitro seedlings of P. taeda, evaluate the use of alternative substrates as well as analyze the effect of pre-germinative treatments for optimizing germination. Disinfestation treatments using sodium hypochlorite, influence of photoperiod and pre-germinative treatments, and the possibility of using alternative substrates (maize star ch, filter paper, hydrophile cotton, vermiculite, agar-water and addition of activated charcoal into the nutritive medium) were tested for germination. In vitro germination, fungal and bacterial contamination were evaluated. The best seed disinfestation treatment was ethanol at 70 % for 30 seconds + sodium hypochlorite at 3 % for 5 minutes. However , it caused a toxic effect. Alternative substrates provide adequate physical conditions to tissue culture, but do not favor germination. Nevertheless, the use of hydrophile cotton associated with seed soaking for 72 hours, without disinfestation, enhances germination and provides in vitro seedlings with low contamination.

In vitro ESTABLISHMENT AND MULTIPLICATION OF GENOTYPES OF Eucalyptus dunnii MAIDEN

This study aimed at evaluating the effect of genotypes of Eucalyptus dunnii on in vitro establishment and also the influence of genotypes grown in different concentrations of 6-Benzylaminopurine (BAP) on in vitro multiplication. Explants were obtained from 10 parent plants selected in the field as a function of their superior phenotype characteristics. For in vitro establishment, 10 genotypes were evaluated, while in vitro multiplication consisted of 30 treatments which corresponded to combinations of six genotypes found to succeed in the in vitro establishment and five BAP concentrations (0, 0.25, 0.50, 0.75, and 1.0 mg L-1). Different behaviors were observed regarding the genotypes as to in vitro establishment rates, in which genotypes 3, 6 and 7 had establishment rates of over 70%, against 40% to 6.6% for the other genotypes. Genotypes 1, 5, 8 and 9 were later discarded due to the reduced number of explants successfully established. Factors such as microbial contamination and phenol oxidation posed a threat to in vitro establishment. The genotypes of Eucalyptus dunnii interacted differently with BAP in in vitro multiplication, noting that the concentration 0.50 mg L-1 positively influenced bud formation on the explants in most genotypes. Hyperhydricity was relatively low when 0.50 mg L-1 BAP was used and thus does not pose a threat to in vitro multiplication of nodal segments of Eucalyptus dunnii.

Formação in vitro de raízes em canafístula: o efeito de diferentes meios de cultivo

Peltophorum dubium (Spreng.) Taub is a forest species native to Brazil endowed with promising forestry features for the purposes of afforestation. However, production of seedlings of high quality through micropropagation is limited by the reduced root formation. As a result, the present study aimed to evaluate the effect of alternative substrates to the agar and the culture period in the in vitro formation of roots. It was tested at 30 and 60 days of in vitro culture, culture media composed of combinations of substrates vermiculite (V), Plantmax® (P) or fine sand (FS) to MS nutritive medium containing 10 µM of 3-indole butyric acid (IBA), with agar or not (A). Was obtained a high survival rate of shoots both the 30 (92.3%) and 60 (82.6%) days of culture. Most culture media yielded high survival (91.1 to 100%) but those containing (P) constituted exceptions. Intense calli formation was observed only after 60 days of culture, in the control, which contained MS and (A), and in those other two treatments containing (V). The best result of root formation as much quantitatively (36.78%) as for the quality were obtained on treatment that included (V) and (A), in addition to MS at 60 days of culture. With the use of (V) in the culture medium there is intense calli formation after 60 days of culture but also there is higher root formation and improvement in the quality when this substrate is combined with nutritive medium MS.

Estabelecimento in vitro de Peltophorum dubium ((Spreng.) Taub.) em função das concentrações do meio MS

Neste trabalho, objetivou-se verificar a influencia de diferentes concentracoes do meio MS no estabelecimento in vitro de segmentos apicais caulinares (80-100 mm) de canafistula isolados, a partir de plântulas germinadas em condicoes assepticas. As concentracoes de sais de 50, 75, 100, 125 e 150% do meio de cultivo MS, foram suplementadas com 30 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 7 g L-1 de agar e o pH, ajustado para 5,7. O delineamento experimental foi o inteiramente casualizado, com 20 repeticoes, cada uma consistindo de um frasco contendo um explante. As culturas foram mantidas por 60 dias em sala de cultivo sob fotoperiodo de 16 horas, intensidade luminosa de 20 µmol m-2 s-1 e temperatura de 25±2oC. Nao houve efeito das diferentes concentracoes do meio MS para a maioria das variaveis, sendo observadas elevadas medias gerais de sobrevivencia (98%) e de estabelecimento (98%) in vitro. O maior numero de folhas (2,8) ocorreu na diluicao de 75%, com reducao a partir dessa diluicao. Nessa mesma concentracao, houve a maxima calogenese, que foi diminuindo ate nao ser observada sob 125% da composicao original; a 150% houve, novamente, presenca de calos. Nao ocorreu enraizamento de explantes durante o cultivo in vitro. Considerando-se o conjunto das variaveis avaliadas e, adicionalmente, que a presenca de calos nao e desejavel, recomenda-se o emprego da concentracao original de sais do meio de cultivo MS no estabelecimento in vitro de segmentos apicais caulinares de canafistula.

In vitro rhizogenesis and acclimatization of Peltophorum dubium shoots: effect of adding agar to a WPM/2 medium with vermiculite

Peltophorum dubium (Sprengel) Taubert is a forest tree that is native to Brazil and that has ecological and economic importance. Preliminary studies on the micropropagation of the species covered aspects of the in vitro establishment and multiplication and indicated that it has potential for this type of asexual propagation. The present study evaluated the in vitro rhizogenesis of P. dubium shoots via micropropagation on different culture media with different concentrations of sucrose, auxin, and agar and analyzed the subsequent in vitro acclimatization of the plantlets. Rhizogenesis was evaluated on half-strength Woody Plant Medium nutritive medium that contained 30 cm3 vermiculite and different concentrations of sucrose (0, 15, or 30 g·L1), the auxin indole-3-butyric acid (0 or 10 μM), and agar (0 or 7 g·L-1). Rooting shoots were transferred to a substrate for in vitro acclimatization. The best medium both for rhizogenesis (producing roots in 44.43% of cases); and for in vitro acclimatization contained 7 g·L-1 agar but no sucrose or auxin. The addition of agar to the medium in the absence of sucrose and indole-3-butyric acid resulted in a better quality radicular system in micropropagated shoots of P. dubium and with a satisfactory survival rate of the plantlets during in vitro acclimatization.

Multiplicação in vitro de segmentos apicais caulinares de segurelha (Satureja hortensis L.)

This study aimed to evaluate the effect of BAP in the presence and absence of NAA, on the in vitro multiplication of shoot apical segments of Satureja hortensis. The explants were isolated from seedlings germinated in vitro and cultured in nutrient medium MS. The experimental design was completely randomized in a 2x5 factorial arrangement, corresponding to the concentrations of NAA (0 and 1 µM) and BAP (0, 5, 10, 15 and 20 µM), with six replicates, each consisting of three explants. For the percentage of explants with shoots, there was no significant effect for the factor BAP, increasing as the concentration of BAP grows. The variable number of shoots per explant showed interaction between factors, with the highest shoot formation in the presence of NAA and BAP in the range of 10 -15 µM. In the presence of auxin, the highest value occurred with 15 µM BAP, tending to decline regardless of the presence of NAA. The rooting of the apical segments was higher in the presence of NAA and absence of BAP, decreasing with increasing cytokinin. Leaf number was influenced by the higher concentration of BAP, and the amount of 15 µMhadthe largest number, tending to decrease with increasing concentration. The concentration of 15 µM BAP, regardless of NAA, provided better results in the multiplication of the species, producing increased number of shoots and leaves, except for rooting, whichwas influenced by auxin.

Superficial disinfestation of isolated explants from semi-hardwood and herbaceous branches of Eugenia involucrate DC. (Myrtaceae).

This study aimed to compare two methods of surface disinfestation of explants isolated from semi-hardwood and herbaceous branches of Eugenia involucrata DC. (Myrtaceae) to obtain aseptic cultures. The better control of bacterial contamination in nodal segments from semi-hardwood branches was obtained by immersion for 25 minutes in sodium hypochloride at 1.5%. However, 39.35% of explants showed bacterial colonies and excessive contamination made it impossible the cultures. Apical and nodal shoot segments derived from herbaceous branches did not differ and showed reduced fungal contamination (13.75%) and bacterial contamination (0.41%), and high in vitro establishment (91.92%). Sodium hypochlorite at 1.5% in the time tested is not efficient in promoting surface disinfestation of nodal segments that already present woody aspects. It is possible to obtain aseptic cultures of E. involucrata for growing shoot apical and nodal segments obtained after the pruning, and sterilized with the aid of mercuric chloride and sodium hypochlorite.

Subsídio hídrico fornecido por substratos alternativos usados na germinação in vitro de Pinus taeda L.

The aim of this study was to assess the water supply provided by different alternative substrates as well as to analyze its efficiency in the sanity and in the in vitro germination of Pinus taeda L. seeds. The seeds were inoculated in filter paper, hydrophile cotton and agar-water medium. Water absorption by seeds was assessed for 3, 6, 9, 24, 48 and 72h and, later, at 21 days of cultivation and contamination by microorganisms was determined. Water absorption, based on the percentage increase which occurred in the weight of seeds, was higher in filter paper and hydrophile cotton. The best germination rates were obtained with filter paper and agar-water. However, agar-water presented the highest contamination rates. Due to water loss in the substrate filter-paper during cultivation, it is suggested the use of cotton because of the low contamination rates observed.