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Ca2+ and nucleotide dependent regulation of voltage dependent anion channels in the plasma membrane of guard cells.
Author(s) -
Hedrich R.,
Busch H.,
Raschke K.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb07608.x
Subject(s) - depolarization , nucleotide , membrane , ion , biology , biophysics , physics , biochemistry , gene , quantum mechanics
Using the patch‐clamp technique we discovered that the voltage dependent anion channels in the plasma membrane of guard cells are activated by a rise in cytoplasmic Ca2+ in the presence of nucleotides. Upon activation, these anion channels catalyse anion currents 10‐20 times higher than in the inactivated state, thus shifting the plasma membrane from a K+ conducting state to an anion conducting state. Prolonged stimulation by depolarizing voltages results in the inactivation of the anion current (t1/2 = 10‐12 s). We suggest that activation of the anion channel by Ca2+ and nucleotides is a key event in the regulation of salt efflux from guard cells during stomatal closure.