Organogênese in vitro na regeneração de clones de Eucalyptus grandis x Eucalyptus urophylla

• Ano de defesa: 2001
• Autor(a) principal: Alves, Elisa Cristina Soares de Carvalho
• Orientador(a): Xavier, Aloisio
• Banca de defesa: Borges, Rita de Cássia Gonçalves , Otoni, Wagner Campos , Dias, José Maria Moreira , Paiva, Haroldo Nogueira de
• 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: Eucalyptus; Micropropagação; Organogênese
• Palavras-chave em Inglês: Eucalyptus; Micropropagation; Organogenesis
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::SILVICULTURA
• Link de acesso: http://locus.ufv.br/handle/123456789/3188

The effects of the growth regulators TDZ, BAP and ANA on the performance of in vitro propagation by organogenesis was evaluated for three hybrid clones of Eucalyptus grandis x Eucalyptus urophylla with leaf and stem explants. These leaf and stem explants were obtained by extended buds in vitro, cultivated in specific culture medium and treated, in each different phase, with different types and concentrations of growth regulators. Combinations of the growth regulators TDZ with ANA and BAP with ANA were used in the callus induction phase under darkness regime, for a period of 35 days. Based on the best treatment obtained during this phase of callus forming, the growth regulators BAP with ANA were evaluated for the phase of buds regeneration, under photoperiod conditions with 16 hours of light and 8 hours of darkness, with an irradiation of 36 mmol m-2s-1, for a period of 35 days. In general, a differentiated response of the clones in relation to intensity, texture, color and oxidation degree of the callus could be observed, due to the growth regulator treatments, for the leaf as well as for the stem explants. For the three examined clones, the best results in cluster forming were observed for the treatments with a combination of the growth regulators TDZ (0.5 mg L -1) and ANA (0.1 mg L-1), achieving 100% of callus forming in the leaf explant. Node formed callus appeared in the petiole region of the leaf explants, and compact node structures, mainly in the extremities of the stem explants. These regions are responsible for the regeneration of adventitious buds in the leaf explants for clone 1 and in the stem explants for clones 1 and 3. The best regeneration response was obtained with 1.0 mg L-1 BAP for clone 1, using leaf explant, and for clone 3, using stem explant. Histological analyses revealed the adventitious origin of the differentiated buds brought forth by leaf and stem explants. However, precaution is recommended in relation to the use of stem explants for regeneration by organogenesis in vitro, due to the possibility of accidental inclusions of axillary buds during the fabrication of the explants, whose production is lower, compared to that of the leaf explant.