Abstract
Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes and potential differences measured that occurred between cell compartments and the flowing bathing medium. The wall developed a Donnan potential that was between -60 and -70 millivolt in 30 millimolar KCl at pH 7. The density of the fixed charges ranged from 0.3 to 0.5 molar; its dependence on pH was almost identical with the titration curve of authentic polygalacturonic acid. The vacuolar potential of guard cells of Commelina communis L., Zea mays L., Nicotiana glauca Graham, Allium cepa L., and Vicia faba L. was between -40 and -50 millivolt in 30 millimolar KCl when stomata were open and about -30 millivolt when stomata were closed. The vacuolar potential of guard cells of C. communis was almost linearly related to stomatal aperture and responded to changes in the ionic strength in the bathing medium in a Nernstian manner. No specificity for any alkali ion (except Li(+)), ammonium, or choline appeared. Lithium caused hyperpolarization. Calcium in concentrations between 1 and 100 millimolar in the medium led to stomatal closure, also caused hyperpolarization, and triggered transient oscillations in the intracellular potential. Gradients in the electrical potential existed across stomatal complexes with open pores. When stomata closed, these gradients almost disappeared or slightly reverted; all epidermal cells were then at potentials near -30 millivolt in 30 millimolar KCl.
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Claims 13
Claim · model-written summary
The guard cell wall developed a Donnan potential between -60 and -70 mV in 30 mM KCl at pH 7.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e1“The wall developed a Donnan potential that was between -60 and -70 millivolt in 30 millimolar KCl at pH 7”
Claim · model-written summary
The density of fixed charges in the guard cell wall ranged from 0.3 to 0.5 molar.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e2“The density of the fixed charges ranged from 0.3 to 0.5 molar”
Claim · model-written summary
The pH dependence of the wall fixed-charge density was almost identical to the titration curve of polygalacturonic acid.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e3“its dependence on pH was almost identical with the titration curve of authentic polygalacturonic acid”
Claim · model-written summary
Vacuolar potential of C. communis guard cells was almost linearly related to stomatal aperture.
- Taxon
- C. communis
Commelina communise6 - Outcome
- vacuolar potentiale6
- Comparator
- stomatal aperturee6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“The vacuolar potential of guard cells of C. communis was almost linearly related to stomatal aperture and responded to changes in the ionic strength in the bathing medium in a Nernstian manner”
Claim · model-written summary
Vacuolar potential of C. communis guard cells responded to ionic strength changes in the bathing medium in a Nernstian manner.
- Taxon
- C. communisCommelina communise6
- Treatment
- changes in the ionic strength in the bathing mediume6
- Outcome
- vacuolar potentiale6
- Qualifier
- in a Nernstian mannere6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“The vacuolar potential of guard cells of C. communis was almost linearly related to stomatal aperture and responded to changes in the ionic strength in the bathing medium in a Nernstian manner”
Claim · model-written summary
Guard cell potential showed no specificity for alkali ions (except Li+), ammonium or choline.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e7“No specificity for any alkali ion (except Li(+)), ammonium, or choline appeared”
Claim · model-written summary
Lithium caused hyperpolarization of guard cells.
Not reportedDirection
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e1“Lithium caused hyperpolarization”
Claim · model-written summary
Calcium at 1 to 100 millimolar in the medium led to stomatal closure.
- Taxon
- several speciese0
- Treatment
- Calcium in concentrations between 1 and 100 millimolare1
- Outcome
- stomatal closuree1
Not reportedDirection
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e1“Calcium in concentrations between 1 and 100 millimolar in the medium led to stomatal closure, also caused hyperpolarization, and triggered transient oscillations in the intracellular potential”
Claim · model-written summary
Calcium at 1 to 100 millimolar in the medium caused hyperpolarization of guard cells.
- Taxon
- several speciese0
- Treatment
- Calcium in concentrations between 1 and 100 millimolare1
- Outcome
- hyperpolarizatione1
Not reportedDirection
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e1“Calcium in concentrations between 1 and 100 millimolar in the medium led to stomatal closure, also caused hyperpolarization, and triggered transient oscillations in the intracellular potential”
Claim · model-written summary
Calcium at 1 to 100 millimolar triggered transient oscillations in the intracellular potential of guard cells.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e1“Calcium in concentrations between 1 and 100 millimolar in the medium led to stomatal closure, also caused hyperpolarization, and triggered transient oscillations in the intracellular potential”
Claim · model-written summary
Gradients in the electrical potential existed across stomatal complexes with open pores.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e2“Gradients in the electrical potential existed across stomatal complexes with open pores”
Claim · model-written summary
When stomata closed, the potential gradients across stomatal complexes almost disappeared or slightly reverted.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e2“When stomata closed, these gradients almost disappeared or slightly reverted”
Claim · model-written summary
With stomata closed, all epidermal cells were at potentials near -30 mV in 30 mM KCl.
Verbatim
e0“Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes”
e2“all epidermal cells were then at potentials near -30 millivolt in 30 millimolar KCl”