Reversible inactivation of K+ channels of Vcia stomatal guard cells following the photolysis of caged inositol 1,4,5-trisphosphate

Nature ◽  
1990 ◽  
Vol 346 (6286) ◽  
pp. 766-769 ◽  
Author(s):  
Michael R. Blatt ◽  
Gerhard Thiel ◽  
David R. Trentham
Keyword(s):  
Guard Cells ◽  
Reversible Inactivation ◽  
K Channels ◽  
Inositol 1,4,5 Trisphosphate ◽  
Stomatal Guard Cells

scholarly journals K+ channels of stomatal guard cells. Characteristics of the inward rectifier and its control by pH.

1992 ◽  
Vol 99 (4) ◽  
pp. 615-644 ◽  
Author(s):  
M R Blatt
Keyword(s):  
Intracellular Ph ◽  
Guard Cells ◽  
Inward Rectifier ◽  
Equilibrium Potential ◽  
Egg Cell ◽  
K Channels ◽  
Inward Rectifiers ◽  
Stomatal Guard Cells ◽  
K Current ◽  
Current Reversal

Intracellular microelectrode recordings and a two-electrode voltage clamp have been used to characterize the current carried by inward rectifying K+ channels of stomatal guard cells from the broadbean, Vicia faba L. Superficially, the current displayed many features common to inward rectifiers of neuromuscular and egg cell membranes. In millimolar external K+ concentrations (Ko+), it activated on hyperpolarization with half-times of 100-200 ms, showed no evidence of time- or voltage-dependent inactivation, and deactivated rapidly (tau approximately 10 ms) on clamping to 0 mV. Steady-state conductance-voltage characteristics indicated an apparent gating charge of 1.3-1.6. Current reversal showed a Nernstian dependence on Ko+ over the range 3-30 mM, and the inward rectifier was found to be highly selective for K+ over other monovalent cations (K+ greater than Rb+ greater than Cs+ much greater than Na+). Unlike the inward rectifiers of animal membranes, the current was blocked by charybdotoxin and alpha-dendrotoxin (Kd much less than 50 nM), as well as by tetraethylammonium chloride (K1/2 = 9.1 mM); gating of the guard cell K+ current was fixed to voltages near -120 mV, independent of Ko+, and the current activated only with supramillimolar K+ outside (EK+ greater than -120 mV). Most striking, however, was inward rectifier sensitivity to [H+] with the K+ current activated reversibly by mild acid external pH. Current through the K+ inward rectifier was found to be largely independent of intracellular pH and the current reversal (equilibrium) potential was unaffected by pHo from 7.4 to 5.5. By contrast, current through the K+ outward rectifier previously characterized in these cells (1988. J. Membr. Biol. 102:235) was largely insensitive to pHo, but was blocked reversibly by acid-going intracellular pH. The action of pHo on the K+ inward rectifier could not be mimicked by extracellular Ca2+ for which changes in activation, deactivation, and conductance were consonant with an effect on surface charge ([Ca2+] less than or equal to 1 mM). Rather, extracellular pH affected activation and deactivation kinetics disproportionately, with acid-going pHo raising the K+ conductance and shifting the conductance-voltage profile positive-going along the voltage axis and into the physiological voltage range. Voltage and pH dependencies for gating were consistent with a single, titratable group (pKa approximately 7 at -200 mV) residing deep within the membrane electric field and accessible from the outside.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of the inward K+-channels in stomatal guard cells by cytoskeletal microtubules

1999 ◽  
Vol 44 (10) ◽  
pp. 919-923 ◽  
Author(s):  
Ximing Zhou ◽  
Weihua Wu ◽  
Ming Yuan ◽  
Xuechen Wang
Keyword(s):  
Guard Cells ◽  
K Channels ◽  
Stomatal Guard Cells

The phenomenon of solar tracking is known from the early studies of Yin (1938) and that it is a blue light response, while the actual photoreceptors involved are not identified (Batschauer 1998; Briggs and Christie, 2002). In view of the fact that solar tracking behaviour results from light-driven turgor changes in the volume of the cells just as in the case of stomatal guard cells, the phototropins might be involved here also (Briggs and Christie, 2002). Sakamoto and Briggs (2002) have suggested that solar tracking may involv e phototropins. The precise molecular mechanisms concernin g the heliotropic movements are not currently known , while some knowledge is available on the mechanism of nyctinastic movements. However, Cronlund and Forseth (1995) have studied the mechanism of soybean leaflet movement and concluded that the mechanism of heliotropic movement was similar to that of nyctinastic movements. These authors have studied the role of K+ channels and the plasma membrane H/ATPase (Michelet and Boutry, 1995) in paraheliotropic movements throug h the measurements of leaf movements after treatment of pulvinus with promoters and inhibitors of HATPase and K+ channels. HATPase inhibition reduced the leaf

2004 ◽  
pp. 101-101
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Light Response ◽  
Guard Cells ◽  
K Channels ◽  
Solar Tracking ◽  
Blue Light Response ◽  
Leaf Movements ◽  
Stomatal Guard Cells

scholarly journals Estimations of apoplastic concentrations of K+ and Ca2+ in the vicinity of stomatal guard cells

1996 ◽  
Vol 134 (3) ◽  
pp. 463-469 ◽  
Author(s):  
D. L. R. SILVA ◽  
SARAH J. HONOUR ◽  
T. A. MANSFIELD
Keyword(s):  
Guard Cells ◽  
Stomatal Guard Cells

scholarly journals Stomatal Guard Cells Co-opted an Ancient ABA-Dependent Desiccation Survival System to Regulate Stomatal Closure

2015 ◽  
Vol 25 (7) ◽  
pp. 928-935 ◽  
Author(s):  
Christof Lind ◽  
Ingo Dreyer ◽  
Enrique J. López-Sanjurjo ◽  
Katharina von Meyer ◽  
Kimitsune Ishizaki ◽  
...  
Keyword(s):  
Stomatal Closure ◽  
Guard Cells ◽  
Stomatal Guard Cells

scholarly journals Submicroscopical Features of Leaves of Xyris Species

2001 ◽  
Vol 44 (4) ◽  
pp. 405-410 ◽  
Author(s):  
Maria das Graças Sajo ◽  
Silvia Rodrigues Machado
Keyword(s):  
Electron Microscope ◽  
Cell Walls ◽  
Guard Cells ◽  
Leaf Ultrastructure ◽  
Mesophyll Cells ◽  
Transmission Electron ◽  
Inner Surface ◽  
Stomatal Guard Cells ◽  
Adaptative Significance ◽  
Scanning Electron

The leaf ultrastructure of five Xyris species were examined using scanning electron microscope (SEM), transmission electron microscope (TEM) and histochemical methods. All studied leaves show some features in epidermis and mesophyll, which were of considerable adaptative significance to drought stress. Such features included the occurrence of a pectic layer on the stomatal guard cells and the presence of a network of pectic compounds in the cuticle. Pectic compunds were also in abundance in lamellated walls of the mesophyll cells and on the inner surface of the sclerified cell walls of the vascular bundle sheaths. There were also specialized chlorenchymatous "peg cells" in the mesophyll and drops of phenolic compounds inside the epidermal cells.

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