Crescimento in vitro e aclimatização de Cyrtopodium aliciae e Cattleya elongata

Abstract

Orchids are valuable plants like ornamental or medicinal, which are collected intensively. Along with those treats, the habitat degradation and intensification of the indiscriminate use of areas for farming, pasture or mining are driving whole populations or species to the extinction. However, the high demand for plants and flowers has encouraged the multiplication and production of seedlings in the laboratory. In nature, orchids are dependent on mycorrhizal fungi to supply the nutritional deficiency of seeds during germination. In the laboratory, germination is performed in vitro and in aseptic environment, free of pathogens. In these conditions it is possible to meet the market demand and preserve the species in their places of origin. The species Cytopodium aliciae and Cattleya elongata are endemic to the Chapada Diamantina National Park. In vitro cultivation of orchids is a technique of germination of higher number of seeds and the formation of healthy seedlings, with growth in the shortest period of time. However, the choice of culture medium should meet the needs of the species in germination, growth and acclimatization. The objective of this work was to evaluate the most efficient culture media for the growth and multiplication of these two species. The culture media used were the Murashige and Skoog (MS) media at half concentration; Vacin and Wendt (V&W) and Knudson C (KC). The experiment was carried out in a completely randomized design with 30 replications containing 10 seedlings in each vial. The variables analysed were: survival rate and total fresh matter mass. The MS medium was the most promising for in vitro and ex vitro growth of Cyrt. aliceae. In C. elongata MS and VW media were better for in vitro growth, in vitro and ex vitro survival rates were efficient in both treatments, while the acclimatization shoot length obtained the better result in KC and VW culture media.