Diurnal changes in storage carbohydrate metabolism in cotyledons of the tropical tree Hymenaea courbaril L. (Leguminosae)

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Autor(es): dc.contributorUniversidade de Brasília, Instituto de Biologia, Departamento de Botânica-
Autor(es): dc.contributorUniversidade de Brasília, Instituto de Biologia, Departamento de Botânica-
Autor(es): dc.contributorUniversidade de São Paulo, Instituto de Biociências, Departamento de Botânica-
Autor(es): dc.creatorAmaral, Lourdes Isabel Velho do-
Autor(es): dc.creatorSantos, Henrique P.-
Autor(es): dc.creatorRossatto, Davi Rodrigo-
Autor(es): dc.creatorBuckeridge, Marcos Silveira-
Autor(es): dc.creatorEmpresa Brasileira de Pesquisa Agropecuária, Centro Nacional de Pesquisa de Uva e Vinho-
Data de aceite: dc.date.accessioned2024-10-23T15:15:31Z-
Data de disponibilização: dc.date.available2024-10-23T15:15:31Z-
Data de envio: dc.date.issued2017-12-07-
Data de envio: dc.date.issued2017-12-07-
Data de envio: dc.date.issued2012-
Fonte completa do material: dc.identifierhttp://repositorio.unb.br/handle/10482/28361-
Fonte completa do material: dc.identifierhttps://dx.doi.org/10.1590/S0100-84042012000400008-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/878516-
Descrição: dc.descriptionThe cotyledons of Hymenaea courbaril store large amounts of xyloglucan, a cell wall polysaccharide that is believed to serve as storage for the period of seedling establishment. During storage mobilisation, xyloglucan seems to be degraded by a continuous process that starts right after radicle protrusion and follows up to the establishment of photosynthesis. Here we show evidence that events related to the hydrolases activities and production (α-xylosidase, β-galactosidase, β-glucosidase and xyloglucan endo-β-transglucosilase) as well as auxin, showed changes that follow the diurnal cycle. The period of higher hydrolases activities was between 6pm and 6am, which is out of phase with photosynthesis. Among the enzymes, α-xilosidase seems to be more important than β-glucosidase and β-galactosidase in the xyloglucan disassembling mechanism. Likewise, the sugars related with sucrose metabolism followed the rhythm of the hydrolases, but starch levels were shown to be practically constant. A high level of auxin was observed during the night, what is compatible with the hypothesis that this hormone would be one of the regulators of the whole process. The probable biological meaning of the existence of such a complex control mechanism during storage mobilisation is likely to be related to a remarkably high level of efficiency of carbon usage by the growing seedling of Hymenaea courbaril, allowing the establishment of very vigorous seedlings in the tropical forest.-
Descrição: dc.descriptionInstituto de Ciências Biológicas (IB)-
Descrição: dc.descriptionDepartamento de Botânica (IB BOT)-
Descrição: dc.descriptionEm processamento-
Formato: dc.formatapplication/pdf-
Idioma: dc.languageen-
Publicador: dc.publisherSociedade Botânica de São Paulo-
Direitos: dc.rightsAcesso Aberto-
Direitos: dc.rights(CC BY NC) This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.-
Palavras-chave: dc.subjectEnzimas - análise-
Palavras-chave: dc.subjectCarboidratos - nutrição-
Título: dc.titleDiurnal changes in storage carbohydrate metabolism in cotyledons of the tropical tree Hymenaea courbaril L. (Leguminosae)-
Tipo de arquivo: dc.typelivro digital-
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