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Percorrer por autor "Nobre, J."

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  • In vitro cloning of Ficus carica L. adult trees
    Publication . Nobre, J.; Romano, Anabela
    The present work reports in vitro studies carried out with two Portuguese cultivars of fig-tree: Berbera (a dried fig) and Lampa (a fresh fig). Procedures were developed to overcome difficulties associated with the establishment of adult material due to contaminants and exudation of phenolic compounds. An improved growth and development of the apical shoot-tips was obtained on Muriithi medium supplemented with 0.05 % PVP. The highest multiplication rate, 5.3 shoots per culture, every three weeks, was achieved on a similar basal medium supplemented with 2.2 mu M BA and devoid of NAA. The best rooting response (96.9 %) was observed on the medium containing 2.5 mu M IBA. Plantlets were successfully acclimatized and grown for three months in the greenhouse, and then field established for orchard production. Micropropagated plants produced fruits two years after field-establishment. These results are a promising step in the direction of in vitro cloning of valuable genotypes directly from field-grown plants and the conservation of plant genetic resources.
    1998Documento de conferência Acesso restrito Ver mais
  • Micropropagation of the Mediterranean species Viburnum tinus
    Publication . Nobre, J.; Santos, C.; Romano, Anabela
    In vitro propagation of the Mediterranean species Viburnum tinus L. was established from an outdoor-grown shrub. Two standard macrosalt formulations (Margara N30K and Murashige and Skoog), a range of benzyladenine and sucrose concentrations were tested for their effect on shoot multiplication. The cytokinin concentration was the most important factor affecting shoot multiplication. The highest shoot multiplication rate was obtained from single-node explants cultured on Murashige and Skoog medium supplemented with 4.4 mu M benzyladenine. Cytokinin concentration and an interaction of macrosalts and benzyladenine influenced shoot length on the multiplication stage: best shoot growth was observed on MS medium containing 1.1 mu M benzyladenine. In addition, sucrose concentrations of 87.6-146.0 mM gave the highest multiplication rates and improved shoot growth. Following a shoot ellongation stage, single shoots were rooted on media containing naphtaleneacetic acid (1.3-5.4 mu M). Although enhanced in vitro rooting was obtained on media containing 5.4 mu M naphtaleneacetic acid, reducing the auxin concentration to 1.3 mu M during the in vitro rooting stage improved acclimatisation frequency and further plant growth in a horticultural substrate.
    2000Artigo científico Acesso restrito Ver mais