ISSN:
1432-2048
Keywords:
Guard cell
;
Ion channel (Stretch activated)
;
Mechanotransduction
;
Patch clamp
;
Voltage-dependence
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Mechanosensitive ion channels in the plasma membrane of Vicia faba guard cell protoplasts were studied by use of the patch clamp technique. Stretch-activated (SA) channels in outside-out patches were analyzed for channel conductance, kinetics and ion selectivity. We found three distinct SA channels, permeable to Cl−, K+ and Ca2+ and distinguishable from spontaneous (non-SA) channels for these ions on the basis of conductance, kinetics, and voltage-dependence, as well as sensitivity to membrane stretch. In the attached patch configuration, light suction (2 to 10 kPa) reversibly induced channel opening with multiple amplitudes and complex kinetics. The open probability for SA channels increased nonlinearly with pipette suction. In guard cells in situ, these SA channels may mediate ion transport across the plasma membrane directly, as well as influence the activity of non-SA channels via effects on membrane voltage and cytoplasmic calcium. Through such effects, SA channels likely influence volume and turgor regulation of guard cells, and thereby control of leaf gas exchange.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00201510
