Calcium-activated, voltage-dependent, non-selective cation currents in endosperm plasma membrane from higher plants

Stoeckel, H.; Takeda, Kenneth

doi:10.1098/rspb.1989.0045

Cited by 40 publications

(25 citation statements)

References 61 publications

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“…Two channels called KORC (K+ outward-rectifying conductance; equivalent to K+,,,) and NORC (nonselective outward-rectifying conductance) become active at membrane voltages more positive than -50 and +30 mV, respectively. NORC channels are nonselective among cations and therefore are similar to outward-rectifying channels described in endosperm cells (Stoeckel and Takeda, 1989). KORC and NORC can reside in the same cell and their respective activation depends on the cytoplasmic Ca2+ level.…”

Section: Loadinc/unloading Of the Xylemmentioning

confidence: 89%

Roles of Higher Plant K+ Channels

Maathuis¹,

Ichida²,

Sanders³

et al. 1997

Plant Physiology

196

123

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Living organisms maintain a cellular solute composition very different from that of the externa1 environment. This implicitly requires the transport of solutes across the cell membrane, and ion channels are integral membrane proteins that play indispensable roles in such transport. In the past dozen years, radical advances have aided in our understanding of ion channel function and regulation in higher plants. Nowhere are these advances more striking than with respect to K+ channels, where the synergistic application of electrophysiological, cell biological, physiological, and molecular techniques has demonstrated an array of channel types playing diverse but defined roles in plant physiology.The major function of K+ channels in animal cells is that of membrane voltage control and short-term repolarization of the membrane. Although K+ channels in plants share similar roles in the regulation of the membrane voltage, early research on guard cells led to the model that shows that plant K+ channels in addition provide important pathways for long-term physiological K+ uptake and release. An extensive range of recent studies suggests diverse longterm transport functions of plant K+ channels, including participation in osmotically driven movements, solute loading into the xylem, cation nutrition, and, by virtue of the presence of K+ channels at endomembranes, intracellular solute redistribution and cytosolic volume control. Most plant K+ channels remain activated for long periods of time, which is critica1 for this proposed long-term transport function of K+ channels in plants. Because higher plant K+ channels are proposed to play a role in regulating both the influx and the efflux of K+ from cells, activity of these channels may impinge upon aspects of turgor and water relations of a11 plant cells. In this Update we focus on important principles of plant K+ channel function and on the proposed physiological roles of specific plant K + channel types in the plasma membrane and tonoplast (Fig. 1A) of different plant cells.

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Section: Loadinc/unloading Of the Xylemmentioning

confidence: 89%

Roles of Higher Plant K+ Channels

Maathuis¹,

Ichida²,

Sanders³

et al. 1997

Plant Physiology

196

123

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“…Although TEA' inhibits the majority of known plant K+ channels (Bentrup, 1990), some TEA+-insensitive K+ channels have been reported, e.g. the Ca2+-dependent K+ channel found in Haemanthus and C h i a endosperm (Stoeckel and Takeda, 1989) and the plasma membrane 49 pS channel from rye roots (White and Tester, 1992). The failure of the LATS to respond to TEAf in Chlamydomonas may be related to the structure and characteristics of this low-affinity transporter.…”

Section: Discussionmentioning

confidence: 99%

Potassium Fluxes in Chlamydomonas reinhardtii (I.Kinetics and Electrical Potentials)

Malhotra

Glass

1995

Plant Physiol.

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“…Channels which were highly selective for cations over anions, but which discriminated poorly between various monovalent cations, have been described in the plasma membrane of triploid endosperm cells from the Amaryllidaceae (Stoeckel & Takeda, 1989). These have an increased probability of being open at depolarized potentials, and had a unitary G of 34 pS in symmetrical 100 mM KCl.…”

Section: Outward Rectifiersmentioning

confidence: 99%

Tansley Review No. 21 Plant ion channels: whole‐cell and single channel studies

Tester¹

1990

New Phytologist

300

166

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SUMMARY Ion channels are proteins which catalyse rapid, passive, electrogenic uniport of ions through pores spanning an otherwise poorly permeable lipid bilayer. Among other processes, fluxes through ion channels are responsible for action potentials – large, transient changes in membrane potential which have been known of in plants for over 100 years. Much disparate information on ion channels in plant cells has accumulated over the past few years. In an attempt to synthesize these data, the properties of at least 18 different ion channels are collated in this review. Channels are initially classified according to ion selectivity (Ca2+, Cl−, K+ and H+); then gating characteristics (i.e. control of opening and closing), unitary conductance and pharmacology are used to distinguish further different sub‐types of channels. To provide a background for this overview, the fundamental properties which define ion channels in animal cells, namely conduction, selectivity and gating, are described. Appropriate techniques for the study of ion channels are also assessed. The review concludes with a discussion on the role of ion channels in plant cells, although any comment on functions beyond turgor regulation and general statements about signalling remains largely speculative. The study of ion channels in plant cells is still at an early stage and it is hoped that this review will provide a framework upon which further work in both algae and vascular plants can be based.

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Calcium-activated, voltage-dependent, non-selective cation currents in endosperm plasma membrane from higher plants

Cited by 40 publications

References 61 publications

Roles of Higher Plant K+ Channels

Roles of Higher Plant K+ Channels

Potassium Fluxes in Chlamydomonas reinhardtii (I.Kinetics and Electrical Potentials)

Tansley Review No. 21 Plant ion channels: whole‐cell and single channel studies

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