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La vitesse de la migration ionique dans les tissus sensibles au froid n'augmente pas immédiatement lors d'une exposition à des températures de réfrigération.

The rate of ion leakage from chilling-sensitive tissue does not immediately increase upon exposure to chilling temperatures.

Auteurs : SALTVEIT M. E.

Type d'article : Article

Résumé

Exposure to non-freezing temperatures below -10 °C causes an increase in the subsequent rate of ion leakage from chilling sensitive tissue (e.g. tomato fruit). The conditions of tissue preparation and conductivity measurements necessary to accurately calculate the rate of ion leakage from excised discs of tomato pericarp tissue were determined. The rate of leakage was linear for the period of 30-240 min following immersion of the discs in aqueous solutions mannitol. A kinetic analysis of the efflux data showed that a combination of two exponential equations, one for a fast extra-cellular reservoir of ions, and one for a `slow' cellular reservoir, fit the original data with an R2>0.95. When measured at 25 °C after chilling, chilling at 2.5 °C for 3.5 days increased the rates of ion leakage. The results showed that changes in membrane permeability occur gradually during chilling and that an abrupt temperature-induced phase transition in membranes may not be the physical event converting exposure to chilling into chilling injury.

Détails

  • Titre original : The rate of ion leakage from chilling-sensitive tissue does not immediately increase upon exposure to chilling temperatures.
  • Identifiant de la fiche : 2003-2362
  • Langues : Anglais
  • Source : Postharvest Biol. Technol. - vol. 26 - n. 3
  • Date d'édition : 11/2002

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