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Ion channels in the vacuoles of the seagrass Posidonia oceanica
Author(s) -
Carpaneto Armando,
Cantu' Alberto M.,
Busch Heiner,
Gambale Franco
Publication year - 1997
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/s0014-5793(97)00786-2
Subject(s) - posidonia oceanica , seagrass , vacuole , ion transporter , ion channel , biophysics , chemistry , conductance , botany , biology , ion , biochemistry , ecology , physics , receptor , organic chemistry , ecosystem , cytoplasm , condensed matter physics
Voltage‐dependent ionic channels were investigated by the patch‐clamp technique in the vacuolar membrane from the leaves of the seagrass Posidonia oceanica . Vacuoles extruded from the meristematic white part of the leaves displayed rectifying slow currents which activated in several seconds at positive potentials and deactivated at negative voltages within a few hundreds of ms. Like the S low V acuolar (SV) channel already identified in the tonoplast of terrestrial plants, the SV voltage‐dependent channel of Posidonia leaves was activated by micromolar concentrations of Ca 2+ and was equally permeable to K + and Na + . The single‐channel conductance of the Posidonia SV‐type channel was 106±12 pS (in symmetric 400 mM K + ). In the same ionic solutions, another channel, occasionally observed in vacuoles from the green part of the leaves, displayed a single‐channel conductance of 47±4 pS. To our knowledge, this is the first electrophysiological characterization of ion transport pathways in Posidonia , a marine plant of crucial importance for the ecology of the Mediterranean sea.