Sodium induces simultaneous changes in cytosolic calcium and pH in salt-tolerant quince protoplasts

• Previousexperimentswithsalt-resistantquinceBA29(Cydonia oblonga cv.Mill.) have shownthatthiscultivartakesupsodiumtransientlyintothecytosolofshoot protoplasts onlyintheabsenceofcalciumchloride,orat o1mMcalciumchloride. Addition ofNaClZ100mMtosingleprotoplastsfrom in vitro-cultivated quinceinthe presence of1.0mMcalciuminducedinstantchangesinthecytosolicconcentrations of calciumandprotons.Thesechangeswereinvestigatedbyuseoftetra [acetoxymethyl] estersofthefluorescentstilbenechromophoresFura2andbis- carboxyethyl-carboxyfluorescein (BCECF),respectively.ThecytosolicCa2+ dynamics in theprotoplastsweredependentontheconcentrationofNaCladded.Thechanges in calciumdifferedinamplitudeandfinalconcentrationandwerecorrelatedintime mainly withchangesinpH.Additionof100–400mMNaCltotheprotoplastscausedan oscillating increaseinthecytosoliclevelofcalcium,andthenadecrease.Addition of mannitol,ofequiosmolarconcentrationtoNaCl,didnotincreasethecytosolic calcium concentration.Moreover,therewasnoincreaseincytosoliccalciumwhen NaCl wasaddedinthepresenceofcalciumbindingethyleneglycol-bis(beta- aminoethylether)-N,N,N0,N0-tetra aceticacid(EGTA),orlantanorverapamil,two inhibitors ofplasmamembranecalciumchannels.Therefore,weconcludethat,in salt-resistant quince,sodiuminducesaninfluxofcalciumintothecytosolbyplasma membrane calciumchannels,andasimultaneousincreaseincytosolicpH.Because these changeswereobtainedinthepresenceof1mMcalciuminthemedium,they were notduetosodiumuptakeintothecytosol.

Subject headings

NATURVETENSKAP  -- Biologi -- Mikrobiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Microbiology (hsv//eng)

Keyword

cytosolic calcium and pH; fluorescence microscopy; Quince; salinity; sodium

Organism biology

Organismbiologi

fysiologisk botanik

Physiological Botany

Publication and Content Type

ref (subject category)

art (subject category)