Composição mineral do meio de cultura para crescimento in vitro de Cattleya walkeriana

• Autor(a) principal: Santos, André Ferreira
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5458
• topic: Orquídeas; Cultivo in vitro; Suprimento nutricional; Orchids; In vitro; Nutrient supply; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

The orchid family has about 30,000 species spread throughout most of the globe. Among the orchids, the group of Cattleya has great importance in the world flower market. One of the main forms of production of these plants is the in vitro assymbiotic seeding. Many have been the culture media used for sowing and growing orchids, however, these methods do not seem to fully supply the nutritional requirements of plants. There is, therefore, great interest in developing new culture media with nutritional composition that supplies properly the demand of the culture during the growing period promoting the production of tissues and the morphogenic response wanted. That was the aim of this work. To adjust the nutrient concentrations in the culture medium suitable for the growth of cattleya seedlings were considered the reference content in their tissues, the dry matter yield production, the volume of culture medium per vial and recovery rates of the nutrients by this culture. This medium was called the medium Supply (S). To compare this medium with others, Cattleya walkeriana protocorms were cultured for 51, 94, 139 and 190 d in MS medium, B5, B & G ( 3 g L-1 of fertilizer Orchidées B&G®), Peters (3 g L-1 of fertilizer Peters® 10-30-20) and S, and tested different concentrations of salts of the latter (0.55, 0.73, 1.00 and 1.45 as the concentration of salts). The medium S, proposed in this work, offered the optimum nutrient supply for the production of seedlings of Cattleya walkeriana when compared with other media. The concentration that provided maximum production of complete seedling was 1.125 time the original concentration of salts of the medium S. The media containing higher concentrations of N and lower P led to the rise in the levels of N and P (TN/TP) in tissue culture, which correlated positively with the ratio of dry matter yield of corn and total. High ratio TN/TP induced reduction in the production of roots. The relationship between the production of roots and leaves increased when the concentration of nutrients in the medium was reduced, because of the consumption of the culture or by reducing the concentration of salt in the medium S.