Micropropagação de clones de Eucalyptus grandis x E. urophylla em biorreatores de imersão temporária

• Ano de defesa: 2009
• Autor(a) principal: Oliveira, Mila Liparize de
• Orientador(a): Xavier, Aloisio
• Banca de defesa: Dias, José Maria Moreira , Pires, Ismael Eleotério
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Ciência Florestal
• Departamento: Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de
• País: BR
• Palavras-chave em Português: Propagagação in vitro; Cultura de tecidos; Propagação clonal; Multiplicação in vitro
• Palavras-chave em Inglês: In vitro propagation; Tissue culture; Clonal propagation; In vitro multiplication
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::SILVICULTURA
• Link de acesso: http://locus.ufv.br/handle/123456789/3025

The use of bioreactors has been an alternative tool for the micropropagation of several species, contributing to the automation in certain phases of the in vitro cultivation, though enabling large-scale production. Accordingly, this study evaluated the micropropagation by means of axillary buds proliferation in the multiplication and elongation stages in vitro of Eucalyptus grandis x E. urophylla clones using temporary immersion bioreactors. During multiplication stage in RITA® bioreactors, experiments were performed with the aim of testing the influence of several factors on fresh weight, number of shoots per explant and hyperhydricity of the culture, among them: culture media (MS, WPM, QL and JADS); BAP and NAA combinations; ratios between nitrogen sources (nitrate and ammonium); cultivation in agar solidified and liquid media; different managements of immersion frequencies (2, 4, 8 and 16 h) and type of support of the explants (filter paper and foam); and a ventilation system with additional air input coupled to the bioreactor containers. In the elongation step, it was evaluated the influence of different periods of cultivation (14, 21, 28 and 35 d) in elongation in vitro of explants cultured in temporary immersion bioreactors RITA® and BIT® (liquid medium) and in plastic pots (semi-solid medium). In multiplication stage, the culture medium MS, the combination of 1.0 μM BAP and 0.5 μM NAA, the ratio 3:1 of N(NO3 -):N(NH4 +), the smallest intervals between immersions (2 and 4 h) and support filter paper promoted greater fresh weight accumulation and number of shoots per explant; for these characteristics, the RITA® system was more efficient as compared to agar-jellified medium. There was a remarkable difference in the development of cultures between the two clones evaluated. The increase in ammonium concentration in the culture medium (1:1, 1:2 and 1:3 of N(NO3 -) :N(NH4 +)) led to smaller effect of explants and the injection of additional air (0.8 L min-1) to the RITA® bioreactor container did not influence the development of the cultures. In general, under the experimental conditions, cultures displayed high percentages of hyperhydricity, and this physiological disorder was a limiting factor for the Eucalyptus cultivation in bioreactors, but not for plants grown in semi-solid agar medium. In the elongation phase, the BIT® bioreactor and cultivation on agar in plastic pots promoted the highest fresh weight accumulation and the final number of shoots at all ages during assessment; however, shoot elongation was not satisfactory, with most shoots (> 60%) within the of class-size of 0.0- 2.0 cm. In conclusion, there is a need to adjust of the culture management in multiplication and elongation steps, in order to obtain shoots with greater vigor and competence to root in ex vitro conditions, in order to make this technique potentially viable to be applied to a large scale shoot production.