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Ion channels in vacuoles from halophytes and glycophytes
Author(s) -
Pantoja Omar,
Dainty Jack,
Blumwald Eduardo
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81067-1
Subject(s) - vacuole , halophyte , chemistry , biophysics , membrane potential , antiporter , ion channel , conductance , potassium , patch clamp , sodium , ion transporter , potassium channel , biochemistry , membrane , biology , salinity , cytoplasm , ecology , receptor , mathematics , organic chemistry , combinatorics
The electrical properties of the vacuolar membrane (tonoplast) of a halophyte, sugar beet, and a glycophyte, tomato, have been investigated using the patch‐clamp technique [(1981) Pflügers Arch. 391, 85–100]. Voltage‐dependent ion channels were analyzed using isolated membrane patches. Both species displayed channel activities which were nonselective between sodium and potassium. Beet tonoplast channels displayed inward rectification (65 pS and 10 pS for negative and positive potentials, respectively), while tomato tonoplast channels showed a constant conductance (25 pS) in the range −80 to +80 mV potentials. The observed low channel conductance at positive potentials in halophytes would prevent a significant loss of the Na + accumulated in the vacuole through the operation of the Na + /H + antiport [(1987) Physiol. Plant. 69, 731–734], while channel rectification in glycophytes would have no physiological significance.