Differential sugar uptake by cell suspension cultures of <Emphasis Type="Italic">Rudgea jasminoides</Emphasis>, a tropical woody Rubiaceae |
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Authors: | Fernanda S Kretzschmar Jr" target="_blank">Clóvis J F OliveiraJr Marcia R Braga |
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Institution: | 1.Se??o de Fisiologia e Bioquímica de Plantas,Instituto de Botanica,S?o Paulo,Brazil;2.Se??o de Ornamentais, Instituto de Botanica,Instituto de Botanica,S?o Paulo,Brazil |
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Abstract: | The primary utilization of carbohydrates by cell suspension cultures of Rudgea jasminoides, a native woody Rubiaceae from tropical forests, was investigated. Sucrose, glucose + fructose, glucose, or fructose were
supplied as carbon sources. The growth curves of R. jasminoides cultured in glucose + fructose, glucose, or fructose showed similar patterns to that observed when sucrose was supplied to
the cells, except that an increase in dry mass was observed at the beginning of the stationary growth phase in the media containing
only one monosaccharide. The increase in hexose levels in the media during the early stages of the cultures indicated extracellular
hydrolysis of sucrose, which was further supported by the increase in the activity of acid invertase bound to the cell wall.
Glucose was preferentially taken up, whereas uptake of fructose was delayed until glucose was nearly depleted from the medium.
Measurements of intracellular sucrose content and cytoplasmatic and vacuolar invertases indicate that the enzymatic activity
seems to be correlated with a decrease in the hexose flux into the cells of R. jasminoides. Our results indicate that the behavior of cell suspension cultures of R. jasminoides regarding sugar utilization seems to be similar to other dicotyledonous undifferentiated cell suspension cultures. |
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Keywords: | Carbohydrates Carbon source Invertase Liquid culture Tropical forests |
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