Whole-cell K+ current across the plasma membrane of guard cells from a grass: Zea mays

Planta ◽  
1992 ◽  
Vol 186 (2) ◽  
Author(s):  
K.A. Fairley-Grenot ◽  
S.M. Assmann
Keyword(s):  
Zea Mays ◽  
Plasma Membrane ◽  
Guard Cells ◽  
Whole Cell ◽  
K Current

scholarly journals K+ transport properties of K+ channels in the plasma membrane of Vicia faba guard cells.

1988 ◽  
Vol 92 (5) ◽  
pp. 667-683 ◽  
Author(s):  
J I Schroeder
Keyword(s):  
Plasma Membrane ◽  
Transport Properties ◽  
Vicia Faba ◽  
Guard Cell ◽  
Guard Cells ◽  
Stomatal Opening ◽  
Whole Cell ◽  
K Channels ◽  
K Transport ◽  
K Currents

Electrical properties of the plasma membrane of guard cell protoplasts isolated from stomates of Vicia faba leaves were studied by application of the whole-cell configuration of the patch-clamp technique. The two types of K+ currents that have recently been identified in guard cells may allow efflux of K+ during stomatal closing, and uptake of K+ during stomatal opening (Schroeder et al., 1987). A detailed characterization of ion transport properties of the inward-rectifying (IK+,in) and the outward-rectifying (IK+,out) K+ conductance is presented here. The permeability ratios of IK+,in and IK+,out currents for K+ over monovalent alkali metal ions were determined. The resulting permeability sequences (PK+ greater than PRb+ greater than PNa+ greater than PLi+ much greater than PCs+) corresponded closely to the ion specificity of guard cell movements in V. faba. Neither K+ currents exhibited significant inactivation when K+ channels were activated for prolonged periods (greater than 10 min). The absence of inactivation may permit long durations of K+ fluxes, which occur during guard cell movements. Activation potentials of inward K+ currents were not shifted when external K+ concentrations were changed. This differs strongly from the behavior of inward-rectifying K+ channels in animal tissue. Blue light and fusicoccin induce hyperpolarization by stimulation of an electrogenic pump. From slow-whole-cell recordings it was concluded that electrogenic pumps require cytoplasmic substrates for full activation and that the magnitude of the pump current is sufficient to drive K+ uptake through IK+,in channels. First, direct evidence was gained for the hypothesis that IK+,in channels are a molecular pathway for K+ accumulation by the finding that IK+,in was blocked by Al3+ ions, which are known to inhibit stomatal opening but not closing. The results presented in this study strongly support a prominent role for IK+,in and IK+,out channels in K+ transport across the plasma membrane of guard cells.

Tonoplast and plasma membrane ATPases from maize lines of high or low vigour

1992 ◽  
Vol 2 (2) ◽  
pp. 105-111 ◽  
Author(s):  
S. Sánchez-Nieto ◽  
R. Rodríguez-Sotres ◽  
P. González-Romo ◽  
I. Bernal-Lugo ◽  
M. Gavilanes-Ruíz
Keyword(s):  
Zea Mays ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Atpase Activity ◽  
Kinetic Analysis ◽  
Atp Hydrolysis ◽  
Membrane Atpases ◽  
Substrate Concentrations ◽  
Tonoplast Atpase ◽  
Specific Inhibitors

AbstractThe effectiveness of ATPase in germinated seed may play an important role in the vigour of germination. The activities of tonoplast and plasma membrane ATPases in two maize (Zea mays L.) lines with different vigour of germination were determined. ATP hydrolysis was measured in microsomal fractions from coleoptiles along with the responses to specific inhibitors for the plasma membrane, tonoplast and mitochondrial ATPases as well as for acid phosphatase. Nitrate-sensitive ATPase activity was 1.5–3.0 times lower in the low-vigour line than in the high-vigour line. Kinetic analysis of ATP hydrolysis at different substrate concentrations revealed the existence of two enzymes in the microsomal fractions of the two lines. The Vmax of enzyme 1 in the low-vigour line was a third of that in the high-vigour line. This enzyme was identified as the nitrate-sensitive or tonoplast ATPase on the basis of measurements of ATP hydrolysis in the presence of specific inhibitors at high (8.12mm) and low (0.77mm) ATP concentrations.

Evidence for electron transport across the plasma membrane of Zea mays root cells

Planta ◽  
1985 ◽  
Vol 165 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Z. -S. Qiu ◽  
B. Rubinstein ◽  
A. I. Stern
Keyword(s):  
Zea Mays ◽  
Plasma Membrane ◽  
Electron Transport ◽  
Root Cells

Modulation of frequency and height of cytosolic calcium spikes by plasma membrane anion channels in guard cells

2021 ◽  
Author(s):  
Md Tahjib-Ul-Arif ◽  
Shintaro Munemasa ◽  
Toshiyuki Nakamura ◽  
Yoshimasa Nakamura ◽  
Yoshiyuki Murata
Keyword(s):  
Plasma Membrane ◽  
Stomatal Closure ◽  
Anion Channel ◽  
Guard Cells ◽  
Cytosolic Calcium ◽  
Peak Height ◽  
Extracellular Calcium ◽  
Wild Type ◽  
Anion Channels ◽  
In The Wild

Abstract Cytosolic calcium ([Ca2+]cyt) elevation activates plasma membrane anion channels in guard cells, which is required for stomatal closure. However, involvement of the anion channels in the [Ca2+]cyt elevation remains unclear. We investigated the involvement using Arabidopsis thaliana anion channel mutants, slac1-4 slah3-3 and slac1-4 almt12-1. Extracellular calcium induced stomatal closure in the wild-type plants but not in the anion channel mutant plants whereas extracellular calcium induced [Ca2+]cyt elevation both in the wild-type guard cells and in the mutant guard cells. The peak height and the number of the [Ca2+]cyt spike were lower and larger in the slac1-4 slah3-3 than in the wild-type and the height and the number in the slac1-4 almt12-1 were much lower and much larger than in the wild-type. These results suggest that the anion channels are involved in the regulation of [Ca2+]cyt elevation in guard cells.

Actin filaments regulate the adhesion between the plasma membrane and the cell wall of tobacco guard cells

PROTOPLASMA ◽  
2017 ◽  
Vol 255 (1) ◽  
pp. 235-245 ◽  
Author(s):  
Qin Yu ◽  
Jing-Jing Ren ◽  
Lan-Jing Kong ◽  
Xiu-Ling Wang
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Actin Filaments ◽  
Guard Cells

scholarly journals Modulation of membrane currents by cyclic AMP in cleavage-arrested Drosophila neurons.

1996 ◽  
Vol 199 (3) ◽  
pp. 537-548
Author(s):  
W B Alshuaib ◽  
L Byerly
Keyword(s):  
Cyclic Amp ◽  
Membrane Currents ◽  
K Channel ◽  
Neuronal Membrane ◽  
Patch Clamp Technique ◽  
Large Variability ◽  
Whole Cell ◽  
Intracellular Environment ◽  
K Current ◽  
Channel Currents

A number of Drosophila learning mutants have defective intracellular second-messenger systems. In an effort to develop techniques that will allow direct measurement of the effects of these mutations on whole-cell neuronal membrane currents, the perforated-patch whole-cell (PPWC) technique has been applied to cleavage-arrested cultured embryonic Drosophila neurons. This technique permits the measurement of membrane currents without disturbing the intracellular environment. As a result of the maintenance of the intracellular environment, Drosophila neuron currents are found to be much more stable than when measured using the conventional whole-cell (CWC) patch-clamp technique. Ca2+ channel currents, which typically 'wash out' within a few minutes of the beginning of CWC recording, are stable for the duration of the seal (tens of minutes) when measured using the PPWC technique. Since the learning mutations dunce and rutabaga disrupt cyclic AMP signalling, the action of externally applied dibutyryl cyclic AMP (db-cAMP) and theophylline on Ca2+ and K+ channel currents were studied. db-cAMP and theophylline enhanced the Ba2+ current, carried by Ca2+ channels, but had no effect on the K+ current in the cleavage-arrested neurons. However, the large variability and reduction in density of Ba2+ and K+ currents raise questions about the suitability of using these cleavage-arrested cells as models for Drosophila neurons.

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