Desinfestação química para semeio e recultivo in vitro de orquídeas e sua influência sobre a nutrição das plântulas

• Autor(a) principal: Fontes, Andréia Aline
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5477
• topic: Orquídeas; Hipoclorito de sódio; Desinfestação; Orchid; Sodium hypochlorite; Disinfestation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

The use of chemical disinfectants such as commercial bleach (CB), for sterilization of culture medium for the propagation in vitro of orchids, is regarded as an efficient and low cost alternative technique compared to autoclave and laminar flow chamber (LFC). However, some questions concerning the type and volume of recipients to be used and the effect on seedling nutrition are yet to be answered. The purpose of this work was to evaluate the use of CB as means of sterilization of culture media for sowing and reculture of orchids, as well as evaluating its effect on different kinds of recipients for sowing and for the nutritional state of recultured seedling. In the first experiment, concerning the sowing, a Laelia tenebrosa Rolfe seed was used in a (3 × 5) + 3 factorial scheme. Regarding the first experiment, three kinds of recipients (a glass recipient one with 340 mL capacity and a polypropylene one with 140 and 340 mL capacity); five doses of CB used in culture medium, 2, 5, 10, 20 e 40 mL L-1; controlled treatment, by using autoclave in the culture medium and sowing in conditions of LFC without the use of CB in the three recipients. In the second experiment (reculture) seedlings of Cattleya kerri Brieger & Bicalho were used. The doses of CB used in the culture medium were 2; 5; 10; 20; 30; 35 e 38 mL L-1, and the doses pulverized over the recultured seedlings were, 5; 12,5; 25; 50; 75; 87,5 e 95 mL L-1. The culture medium of the controlled treatment was autoclaved and reculture in LFC conditions. The proportion of germinated seeds, oxidized seeds, seedlings formed and the dry matter of protocorms were bigger in the controlled treatment. The higher doses of CB used in culture medium had worse results in the germination in glass recipient if compared to the polypropylene ones which had no difference in plant growth according to the dose apllied. In the reculture, in respect to the autoclaved recipient and the sterilized ones with a lower CB concentration, there were no considerable differences between the number of sprouting, leafs and roots, mean height and dry matter mass. The increase in the CB dose negatively influenced the seedling growth and had little influence on its nutritional status.