A slow anion channel in guard cells, activating at large hyperpolarization, may be principal for stomatal closing

FEBS Letters

Linder, Birgit¹  Raschke, Klaus¹ 

[1] Pflanzenphysiologisches Institut und Botanischer Garten der Universität Göttingen, W-3400 Göttingen, Germany

关键词: Anion channel;    Patch clamp;    Stomatal closure;    Voltage dependence;    EGTA;    Ethylene glycol bis(2-aminoethylether)-N;    N;    N′Ń-tetraacetic acid;    HEDTA;    N-Hydroxyethylethylenediaminetriacetic acid;    MES;    2-N-morpholinolethanesulfonic acid;    Tris;    Tris [hydroxymethyl]aminomethane;   

DOI  :  10.1016/0014-5793(92)81176-M

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Slowly activating anion channel currents were discovered at micromolar ‘cytoplasmic’ Ca²⁺ during patch-clamp measurements on guard-cell protoplasts of Vicia faba and Xanthium strumarium. They activated at potentials as low as −200 Mv, with time constants between 5 and 60 s, and no inactivation. The broad voltage dependence exhibited a current maximum near −40 mV. The single-channel open time was in the order of seconds, and the unitary conductance was 33 ps, similar to that of the already described ‘quick’ anion channel of guard cells. Because of its activity at low potentials, the slow anion channel may be essential for the depolarization of the plasmalemma that is required for salt efflux during stomatal closing.

【 授权许可】

Unknown