Germinação e mobilização de reservas de sementes de macaúba (Acrocomia aculeata (Jacq.) Lodd. ex Martius)

• Ano de defesa: 2011
• Autor(a) principal: Bicalho, Elisa Monteze
• Orientador(a): Motoike, Sérgio Yoshimitsu
• Banca de defesa: Guimarães, Valéria Monteze , Silva, Marco Aurélio Pedron e
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Fisiologia de sementes florestal; Histoquímica; Anatomia
• Palavras-chave em Inglês: Physiology of forest seeds; Histochemical; Anatomy
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4556

The aims of this work were to study the germination process of macaw palm seeds through the activities of the enzymes β-mannanase and α-galactosidase, and quantify the amount of mannan present in the endosperm cells. In addition, we studied the dynamics of mobilization of lipid, protein and starch reserves by biochemical and histochemical analysis. The seeds were submitted to a protocol to overcame the species dormancy (patent application: PI0703180-7) and macaw palm germination process was followed up to 29 days. Analyses were performed in embryo / haustorium and lateral and micropylar endosperm separately. The activities of the enzymes β-mannanase and α-galactosidase were performed by colorimetric methods in a spectrophotometer using guar gum and pnitrophenyl-D-galactopyranoside (pNPGal), as substrates, respectively. The content of mannan was analysed by gas chromatography, the lipid by the gravimetric method in the extraction apparatus, the starch by the phenol-sulfuric and soluble protein by Breadford method. Histochemical tests were performed to corifosfina of pectin, cellulose material to calcofluor, Sudan Black B for total lipids, lugol for detection of starch, XP for protein and safrablau for staining and characterization. The activities of β-mannanase and α-galactosidase were higher in the endosperm to the embryo / haustorium throughout the germination period studied. The activities of both enzymes increased in the endosperm after the protrusion of the cotyledon petiole but in the embryo/ haustorium only the β-mannanase activity increased. At the same time, the content of mannan reduced in the endosperm. The lipid content reduced in the embryo from the protrusion of the cotyledon petiole, but increased in the endosperm during the period studied. The Sudan Black B test showed a reduction in number and size of lipid bodies in the embryo. Right after the protrusion of the cotyledonary petiole were identified starch grains, marked with Lugol test, being formed in the haustorium and increasing in quantity until the end of evaluations. In this phase the starch content in the embryo / haustorium increased exponentially. The starch in the endosperm was not identified by lugol histochimical test. The protein content decreased continuously in the embryo / haustorium from the start of imbibition, however, has not changed in the endosperm. The XP test showed qualitative loss of staining of protein bodies in the embryo / haustorium over time. The results suggest that the two enzymes studied are mainly involved in the mobilization of mannans and / or galactomannans of the endosperm after germination. The embryo possesses reserves that provide energy to the early metabolic events of germination. In the endosperm, lipid and protein reserves have not been accessed during the period studied, but there was intense degradation of cell wall polysaccharides from the endosperm side of germination in the strict sense.