Percorrer por autor "Noronha, C."
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- Influence of growth-regulators on shoot proliferation in Quercus-Suber LPublication . Romano, Anabela; Noronha, C.; Martins-Loução, M. A.Procedures have been developed to standardize the multiplication stage during mature cork-oak (Quercus suber L.) micropropagation. Axillary and terminal buds were established on Gresshoff and Doy basal medium containing 1 mg I−1 of 6-benzylaminopurine (BAP). Initiation of cultures was possible all over the year. The effects of BAP, Z, IBA, 1AA and NAA and various nutrient formulae on shoot growth and proliferation was investigated. BAP was more suitable than zeatin. Shoot proliferation and elongation were strongly improved by the combination BAP/IAA in the presence of low salt media, like Gresshoff and Doy or Woody Plant medium. Both rates were significantly increased when a double-phase culture system was used. Shoots have been multiplied for 1 year at the rate of three to four-fold every 4 weeks without any decline of vigour. Rooting was achieved by briefly dipping the basal ends of in vitro regenerated shoots in an IBA concentrated solution. The results here reported constitute a promising step towards large scale in vitro propagation of a species in which conventional vegetative propagation by cuttings is very difficult.
- Role of carbohydrates in micropropagation of cork oakPublication . Romano, Anabela; Noronha, C.; Martins-Loução, M. A.The influences of carbon sources, fructose, glucose, sorbitol and sucrose on shoot proliferation and in vitro rooting of cork oak (Quercus suber L.) were compared at a wide range of concentrations (1-6%, w/v). The highest number of shoots occurred on glucose-containing medium. Nevertheless, we have chosen 3% sucrose which induced a similar rate of proliferation but favoured shoot elongation, permitting an effectively higher number of shoots during transfers. Sorbitol and autoclaved fructose did not stimulate shoot proliferation. Adventitious root formation was strongly dependent on carbohydrate supply. Sorbitol and autoclaved fructose were completely ineffectively on rooting induction. Glucose was the most effective carbon source on rooting promotion followed by sucrose and filter-sterilized fructose. The rooting response induced by fructose was dependent on the sterilizing procedure. The number of adventitious roots produced per shoot increased with increasing glucose and sucrose concentration. The content of reducing sugars in leaves of proliferation cultures and in leaves and roots of rooted plantlets was more dependent on carbon concentration than on glucose or sucrose supplement. The results presented here show that carbohydrate requirements during cork oak micropropagation depend upon the phase of culture. Sucrose (3%) and glucose (4%) were the best carbon sources respectively during proliferation and rooting phases.