Micropropagation of Cattleya loddigesii âTipoâ: nitrogen sources, light quality, sucrose and giberelic acid. / MicropropagaÃÃo de Cattleya loddigesii Tipo : Fontes de NitrogÃnio, Qualidade de Luz, Sacarose e Ãcido GiberÃlico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The aim of this present work was to study the in vitro development of Cattleya loddigesii âTipoâ, as well as the anatomical alterations under different in vitro culture environments. Four separate experiments were made to evaluate: 1) The influence of different nitrogen sources, calcium nitrate (0, 278, 556, 834 and 1112 mg L-1) x ammonium nitrate (0, 200, 400, 600 and 800 mg L-1); 2) light quality (yellow, blue, white, green and red) x GA3 concentrations (0; 2.5; 5.0; 10.0; and 20.0 mg L-1); 3) culture environments (CV: greenhouse, CVA: greenhouse with a blue shading net, CVV: greenhouse with a red shading net, SC: artificial light growth room, SCA: artificial light growth room with a blue shading net, and SCV: artificial light growth room with a red shading net) x different sucrose concentrations (0, 20, 40 and 60 g L-1); and 4) the effect of colored shading nets (red and blue) on the flasks cultivated in greenhouses (CV) and growth rooms (SC). The explants used were 1 to 1.5 cm in length plantlets produced by self pollinization flowers and in vitro germinated seeds, containing roots. The assessment were made after 90 and 180 days from the begining of the experiment. It was verified that the use of WPM medium without calcium nitrate was the best treatment to the micropropagation of the Cattleya loddigesii âTipoâ. The culture room environment with red cellophane enhances the elongation of the plantlets. The presence of GA3 in the culture medium affected the rooting system development and also in the increase of the biomass. The best in vitro development was obtained with 15 g L-1 of sucrose in a conventional growth room with artificial white lamps. However the highest rooting rates and dry wheight of the plantlets were verified in the medium supplemented with 45 g L-1 of sucrose, no influence of the culture environment was observed. The culture environment is responsible for the promotion of anatomical and morphological alterations in Cattleya loddigesii âTipoâ, during in vitro cultivation. The explants under a natural light greenhouse promoted the development of a well adapted leaf surface, in terms of anatomical variables, in the acclimatization phase.

ASSUNTO(S)

cattleya orchidaceae meio de cultura fitotecnia orchidaceae crescimento in vitro in vitro growth culture media anatomy light quality anatomia regulador de crescimento cattleya qualidade de luz

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