Propaga??o in vitro de sacaca (Croton cajucara Benth.): entendimentos sobre a dificuldade no desenvolvimento de protocolos de micropropaga??o da espécie

摘要

http://dx.doi.org/10.5007/2175-7925.2015v28n4p41 Sacaca is a medicinal plant from the Amazonian biome and it has been regarded as a substitute for rosewood ( Aniba roseaodora ) to produce linalool. This paper aimed to evaluate in vitro vegetative propagation of sacaca, including the establishment of propagules from the field, decontamination protocols, and determination of multiplication rates, besides describing limiting aspects for the culture during in vitro experiments. We used 1.0 cm microcuttings with an axillary bud, collected from adult plants in the field. Disinfestation treatments were tested in the establishment, and there is an evaluation of the collecting month influence on the contamination rates. After disinfestation, microcuttings were placed in test tubes containing MS medium, added with BAP (0, 1, 2 and 3 mg L -1 ) and GA 3 (0 and 0.5 mg L -1 ). In vitro establishment of sacaca with 41.9% of sprouted microcuttings was obtained. The contamination rate reached 58.1% (65.4% caused by fungi and 34.6% by bacteria), with greater occurrence when propagules were collected between October and January, the rainiest months in the Amazon region. The increased BAP and GA 3 concentrations in the culture medium provided significant improvements in the material multiplication rates. In spite of the results obtained, the species shows peculiarities and limitations to in vitro cultivation that were identified and described in this paper.