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ACTIVITE DE LA POMPE DE Na+ - K+ CHEZ LE SANDRE
AU COURS DE SON ACCLIMATION AUX CONDITIONS DE SALINITE
DE LA MER NOIRE

V. Craciun 1), Margareta Craciun 1), I. Neacsu 1)
et I. Trandafirescu 2) 

1) Centre de Recherches Biologiques Iasi
2) Institut Roumain de Recherches Marines Constanta

Abstract
Na+ and K+ dependent ATP-ase activity from gills and gut
of your pikeperch has been investigated during sudden and
gradual transfer from freshwater to brackish water (8-12.8 g S%).
Gradual transfer to salinities as normal for the Black Sea
(12-16 g S%) induce the reduction of ATP-ase activity, 
according to the new osmotic equilibrium established. Sudden
transfer in seawater induces initially the reduction of the 
enzymatic activity, followed by recovery; the intens osmotic
claim imposed by such conditions my explain the death of the
experimental subjects.