Flávio Zanette

Micropropagação de Aspidosperma polyneuron (peroba-rosa) a partir de segmentos nodais de mudas juvenis

The objective of the present work was to establish a micropropagation protocol of Aspidosperma polyneuron from juvenile material. Apical shoots from two years old seedlings were collected in a greenhouse and sterilised with NaOCl or HgCl2 to establish aseptic cultures. Multiple shoots induction was evaluated in WPM medium, supplemented with BAP, ZEA or KIN (2.2 - 8.8 µM) in initial culture and two subsequent subcultures. The elongation of shoots was tested with growth regulators combinations: 2.25 µM of BAP, ZEA or KIN with 1.25 µM of IBA. IBA treatments (2.5; 5.0 and 10 mM) were tested with 5 and 15 minutes to induce roots. Plantlets were planted in a greenhouse. Efficient apical shoots sterilization was achieved with NaOCl (0,25% - 10 minutes) or HgCl2 (0.05%-10 minutes); survival rates were 72.89% and 84,10%, respectively. Apical shoots induced 4-5 axillary buds in WPM culture medium, containing ZEA or BAP (4.4 - 8.8 µM) following two subcultures. Reduced concentrations of ZEA or BAP (2.25 µM), combined with IBA (1.25) produced elongated shoots. IBA treatment (10 mM) during 15 minutes induced higher rooting percentages (80%). Plantlets planted in a greenhouse showed higher survival rates (90%).

Influence of calcium content of tissue on hyperhydricity and shoot-tip necrosis of in vitro regenerated shoots of Lavandula angustifolia Mill.

In the present study, the effects of two CaCl2.2H2O levels (440 and 1320 mg L-1) and two subcultures were evaluated on in vitro shoots of Lavandula angustifolia cv. Provence Blue. Ca2+ content of the apical, middle and basal portion of shoots was determined. Increasing CaCl2.2H2O level in the culture medium increased tissue Ca2+ content and decreased hyperhydricity. Shoot-tip necrosis also decreased with 1320 mg L-1 CaCl2.2H2O, but it did not occur in the second subculture. The middle and basal portion had higher Ca2+ content than apical portion. In non-hyperhydric tissues, there were smaller and more juxtaposed cells. Scanning electron microscopy of the leaves demonstrated that trichomes from in vitro leaf surface occurred in smaller quantities.

Estabelecimento de culturas assépticas de Aspidosperma polyneuron .

The objective of the present work was to obtain aseptic cultures in order to establish a micropropagation protocol of Aspidosperma polyneuron from juvenile explants. Apical shoots from two-year--old seedlings were collected in a greenhouse and disinfected with sodium hypochlorite (0.125 or 0.25%) or mercuric chloride (0.025, 0.05 or 0.1%), during 5 or 10 minutes and at different seasons of the year. Necrosis, bacterial and fungal contamination percentages and survival rates were evaluated after three weeks. It was showed that NaOCl 0.25% solution, during 10 minutes resulted in 70% of survival and disinfection of apical shoots, independent of the season of the year (summer or autumn). HgCl 2 was more efficient than NaOCl in the disinfection of apical shoots, therefore 0.05% HgCl 2 , during 10 minutes was recommended (84.10% of survival). Aseptic cultures were established in all seasons of the year, but better results were obtained in spring and summer.

Grafting of Araucaria angustifolia (BERTOL.) kuntze through the four seasons of the year

A Araucaria angustifolia, especie quase exclusiva do Brasil, esta ameacada de extincao devido a extracao predatoria de sua madeira. E fundamental incentivar o plantio desta especie, pois desempenha um papel-chave na conservacao do ecossistema. Produzir mudas com caracteristicas que incentivem o plantio e muito importante. A enxertia das mudas pode propiciar a precocidade reprodutiva com producao antecipada de pinhoes de alta qualidade. O pinhao, semente da araucaria, tem alto valor nutritivo, e rico em amido e proteina, sendo desta forma uma excelente opcao alimentar para a populacao. A comercializacao de pinhoes pode ser uma saida para estimular o plantio da especie. O objetivo deste trabalho foi determinar a melhor epoca do ano para se fazer a enxertia. Foram utilizadas plantas de dois anos e meio de idade como porta-enxerto e ramos ortotropicos jovens de plantas adultas para os enxertos. A tecnica usada para a enxertia foi a placagem lenhosa. Este procedimento foi realizado no inicio de cada estacao do ano, totalizando 160 enxertos. Os enxertos realizados no inicio do outono tiveram, em media, 50% de sobrevivencia. Nas demais estacoes, os resultados foram inferiores. Conclui-se que a enxertia por placagem e tecnicamente viavel para a producao de mudas de A. angustifolia, e o melhor periodo para enxertar e no inicio do outono.

Somatic Embryogenesis in Aspidosperma polyneuron Mull. Arg.

Aspidosperma polyneuron, a representative of Apocynaceae family, is a species of great economic importance for the forestry sector. It is under a serious risk of extinction in Brazil and Venezuela (Figure 1A). Therefore, there is a great need of a germplasm conservation program for this species. This species grows at the Semidecidous Stational Forest being listed as rare and endangered in the State of Parana, Brazil, where it is a native tree (Hatschbach and Ziller, 1995).

Screening of acetogenin-producing plants in Brazilian flora

The acetogenins are strongly bioactive natural compounds present in the bark, roots, leaves, and seeds of manyAnnonaceae plants. They are modified fatty acids and their cytotoxicities have been determined for different biological models including the in vitro growth inhibition of several human cancer cell lines.Very low acetogenin yield (< 0.1 g%) has been found previously in native phytobiomass, and we have now investigated the nonpredatory exploitation of the seeds as acetogenin sources characterizing the seed triacylglycerols (dominant fraction; > 90% of the whole lipid extracts) as potential valuable by-products.Supercritical fluid extraction (SFE) was utilized as an alternative for both kinds of lipid biomass, acetogenins and fats, and manipulation ofAnnona expiants for obtaining in vitro callus and/or new plants.

Propagação in vitro e caracterização química do óleo essencial de Lavandula angustifolia cultivada no Sul do Brasil

Lavandula angustifolia Mill. e uma importante planta produtora de oleos essenciais, que apresenta dificuldade de propagacao pelo enraizamento de estacas, sendo a producao de mudas realizada nesse trabalho pela tecnica de micropropagacao, em que foram avaliadas algumas condicoes do cultivo in vitro. As mudas produzidas pela micropropagacao foram cultivadas em Sao Joaquim (SC). O oleo essencial das inflorescencias foi extraido por hidrodestilacao, e analisado quanto a sua composicao por GC/MS, em dois anos de colheita. O meio de cultura LS apresentou melhor resposta no desenvolvimento das brotacoes, nao sendo observadas brotacoes com necrose apical. Meios de cultura mais diluidos como o ½ MS e o WPM, apresentaram altas taxas de hiperidricidade e necrose apical das brotacoes. A citocinina BAP influenciou a multiplicacao das brotacoes, sendo a qualidade mantida com 1,0µM ao longo de quatro subcultivos. A sobrevivencia das plantas na aclimatizacao foi de 80%. Os teores de oleo essencial foram de 4,0% e 5,25%, na primeira e segunda colheita, respectivamente. Os compostos majoritarios foram o linalol (46,88% e 37,25%) e acetato de linalila (10,09% e 12,24%).

Enraizamento de miniestacas de espinheira-santa (Maytenus ilicifolia Mart. ex Reissek) em diferentes substratos

Pertencente a familia Celastraceae, a espinheira-santa (Maytenus ilicifolia Mart. ex Reissek) e uma especie medicinal nativa da regiao sul do Brasil, utilizadas no tratamento de gastrite e ulceras gastricas. Estudos sobre a producao de mudas por meio de estaquia demonstraram que esta especie e considerada de dificil enraizamento. Objetivou-se, no presente trabalho, avaliar os efeitos de diferentes substratos no enraizamento de miniestacas de espinheira-santa. Miniestacas apicais foram coletadas a partir das brotacoes das minicepas de 10 meses de idade, mantidas em casa-de-vegetacao e confeccionadas com 3 a 4cm de comprimento, mantendo-se duas folhas com a superficie reduzida a metade. O plantio foi realizado em caixas contendo areia e tubetes contendo casca de arroz carbonizada, Plantmax HT® ou vermiculita de granulometria fina como substrato. As miniestacas foram mantidas em casa-de-vegetacao com nebulizacao intermitente e 90 dias apos o plantio, foram avaliadas as caracteristicas: porcentagem de estacas enraizadas, numero e comprimento medio de raizes, porcentagem de estacas com calos, sobrevivencia e mortalidade. O delineamento experimental foi inteiramente casualizado, com 4 tratamentos e 4 repeticoes de 22 estacas por parcela. A analise estatistica revelou que os substratos areia (92,04%), casca de arroz carbonizada (88,66%) e Plantmax HT® (94,31%) apresentaram indices de enraizamento significativamente superiores a vermiculita (78,41%), alem de menores taxas de mortalidade, sendo que a propagacao vegetativa de espinheira-santa por meio de miniestaquia e viavel.

Microenxertia e sua caracterização morfológica em Araucaria angustifolia

O objetivo deste trabalho foi determinar a melhor tecnica para microenxertia em Araucaria angustifolia. Para isto, foram realizadas auto-enxertias em plantas germinadas in vitro, com 2, 6 e 12 meses de idade. Foram testados dois locais de enxertia no porta-enxerto: caule e hipocotilo, e dois tipos de enxertia: garfagem de topo com e sem fenda. A maior porcentagem de microenxertos com fenda aberta ocorreu nas microenxertias realizadas no hipocotilo. As maiores porcentagens de microenxertos sobreviventes foram obtidas nas microenxertias realizadas no caule, e o tipo de enxertia mais eficiente foi a garfagem de topo sem fenda. A presenca de calo aparente foi resultado da interacao dos tres fatores testados, com maior presenca de calo nas enxertias realizadas no hipocotilo. O crescimento dos microenxertos indicou o restabelecimento das conexoes vasculares. O maior crescimento dos microenxertos foi obtido nas enxertias realizadas no caule em porta-enxertos de 6 meses com a garfagem de topo. As metodologias testadas permitem concluir que o processo de microenxertia em Araucaria angustifolia e eficiente e factivel, podendo ser utilizado para a producao de mudas microenxertadas.

Impact of monoecy in the genetic structure of a predominately dioecious conifer species, Araucaria angustifolia (Bert.) O. Kuntze

Understanding the mating system of a tree species is important in genetic conservation and tree breeding strategies because it affects the inbreeding and genetic diversity of the descendant populations. Araucaria angustifolia (Bert.) O. Kuntze is a mainly dioecious species that reproduces through outcrossing. However, some monoecious trees have been identified and they may reproduce through self-fertilization. The objective of this study was to confirm the expected relatedness of full-sibs in outcrossed hand-pollinated progenies of female seed trees, self-sibs of hand self-pollinated monoecious seed trees, and to investigate the mating system of open-pollinated progenies of female and monoecious A. angustifolia trees. To do this, eight microsatellite loci were used to genotype hand- and open-pollinated progenies. Our results show that the relatedness of outcrossed hand-pollinated progenies are true full-sibs and progenies from a selfed monoecious seed tree are self-sibs, which confirms the hand-pollination method used. Open-pollinated female seed trees reproduced only by outcrossing, generating progenies with a mixture of full- and half-sibs. Monoecious seed trees reproduced mainly by xenogamy, generating progenies with mixtures of self-sibs, full-sibs, half-sibs and self-half-sibs. We also found that an increase in the effective number of pollen donors (