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Açucares soluveis, sacarose sintase e sacarose fosfato sintase durante o desenvolvimento do fruto de café, sob diferentes condições de luz e carga

Geromel C., Mazzafera P., Marraccini P., Ferreira L.P., Vieira L.G.E., Perreira L.F.P.. 2005. In : Anais do IV Simposio de Pesquisa dos Cafés do Brasil, 2 a 5 de Maio de 2005, Londrina, PR (Brasil). Brasilia : EMBRAPA, 3 p.. Simposio de Pesquisa dos Cafés do Brasil. 4, 2005-05-02/2005-05-05, Londrina (Brésil).

The physiological aspects of carbohydrate metabolism and the sink-source relationship were studied. Sucrose was the main sugar transported to fruits in coffee. Sucrose is not promptly used as substrate in most of the process related with growth, development and storage in source or sink tissues. It is first metabolized by invertases, sucrose synthase (SUSY) and sucrose phosphate synthase (SPS). The activities of SUSY and SPS as well as the contents of reducing sugars, sucrose and total soluble sugars were determined in the pulp, perisperm and endosperm during the development of coffee fruits, from plants under full sunlight (control), 50% light and carrying 30% of the fruits. Fruits were manually removed from the later treatment and the 50% light intensity was provided by a plastic screen (50% light cut-off). It was shown that although SUSY and SPS have lower activity in the treatments of less light and less fruits, the contents of sugars did not vary accordingly. It was observed the same pattern for enzyme activities in the tissues in the three treatments, an increase with maturation.

Mots-clés : coffea; saccharose; ligase; métabolisme des glucides; activité enzymatique; développement biologique; fruit (botanique); fève de café; facteur du milieu; lumière du jour; enzyme; synthétase; sink effect

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