Aspectos relacionados à competência organogenética de meristemas caulinares de Dendrobium Second Love (Orchidaceae) / Aspects of Dendrobium second love shoot meristems (Orchidaceae) related to organogenetic competence

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

In vitro tissues, organs or plants culture has been widely used as a micropropagation technique aiming to study a number of factors involved in vegetable growth and development. In the present study, we evaluated the physiological conditions related to different vegetative or reproductive organogenetic responses in in vitro Dendrobium Second Love (Orchidaceae) plants. We evaluated the organogenetic potential of the shoot segments in inducing explants for the regeneration of new in vitro plants and their morphological changes. This technique was also micropropagated with light incubation of the plants in order to provide enough material for the study of the participation of TDZ, Z, ZR, iP, iPR in the induction of their budding and its flowering. Thus, it was possible to analyze the endogenous levels of soluble sugars, ethylene concentration, following the application of these cytokinins, as well as evaluated the effect of treatment duration and the plant age. The results showed that the plant incubation age is not only important to generate new plants, but also to induce its budding and flowering, irrespective of the dark/light condition. Successives tests showed that the main reason for changes in the organogenetic potential of the explants was due to the etiolated plant region, as well the tissue age. In this sense, lower dark incubation length led to an increase in the percentage of plants regeneration, and to more homogeneous plant sizes. Among the studied conditions, all cytokinins induced budding, however concerning flowering only TDZ was effective. It was also verified that a 10-day exposure to TDZ can induce plants to flowering. The level of soluble sugars in the buds submitted to the treatment with Z, ZR, iP, iPR and TDZ was higher in the ones treated with TDZ, suggesting a higher sugar use in the plants induced flowering. Regarding the ethylene accumulation in the flasks, it was observed that plants treated with TDZ induced higher ethylene accumulation when compared to control plants.

ASSUNTO(S)

meristemas caulinares plant hormone organogênese organogeneses shoot meristems hormônios vegetais

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