Guard cell pressure/aperture characteristics measured with the pressure probe

Franks, Peter J.; Cowan, I. R.; Tyerman, Stephen D.; Cleary, Ann L.; Lloyd, John William; Farquhar, Graham D.

doi:10.1111/j.1365-3040.1995.tb00583.x

Cited by 60 publications

(61 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Between c and d and again in f through h (Fig. 5), application of pressure resulted in oil injection into the cell, a clear indication of a pressure increase in the cell (Franks et al, 1995). A welldefined interface between the oil and the cellular contents was always observed, indicating that the oil was not dispersing and not affecting cellular contents by mixing.…”

Section: Effect Of Pressure Modulation By Oil Lnjectionmentioning

confidence: 94%

“…Upon impalement, free movement of the oil/ aqueous interface during pressure modulation was an absolute necessity to ensure that plugging of the tip was not affecting the equilibration of pressure between the probe and the cell (Franks et al, 1995). After a pressure pulse was applied, oil movement could continue for a short period (severa1 seconds), indicating some restriction to oil flow at the tip.…”

Section: Pressure-probe Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Pressure Regulation of the Electrical Properties of Growing Arabidopsis thaliana L. Root Hairs

Lew

1996

Plant Physiology

View full text Add to dashboard Cite

Section: Effect Of Pressure Modulation By Oil Lnjectionmentioning

confidence: 94%

Section: Pressure-probe Measurementsmentioning

confidence: 99%

Pressure Regulation of the Electrical Properties of Growing Arabidopsis thaliana L. Root Hairs

Lew

1996

Plant Physiology

View full text Add to dashboard Cite

“…FM 4-64 and related dyes have been well characterized as markers for membrane internalization by endocytosis (Vida and Emr, 1995), and our data clearly show that that FM 4-64 was excluded from the cell except when volume was reduced osmotically. Based on estimates and measurements of guard cell turgor pressure in V. faba (Franks et al, 1998(Franks et al, , 2001, even the largest osmotic potentials of the external solutions used in this study should not have been sufficient to reduce guard cell turgor pressure to zero, and comparison of our data with pressure probe measurements of the relationship between stomatal aperture and guard cell turgor in V. faba (Franks et al, 1995(Franks et al, , 2001 suggests that the maximum turgor pressure of our cells was between 3.0 and 4.0 MPa. Because the largest osmotic potential used in this study was 1.5 MPa, and membrane internalization and loss of surface area were evident for increases in osmotic potential as small as 0.3 MPa, it seems almost certain that membrane internaliza- …”

Section: Discussionmentioning

confidence: 99%

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

2003

View full text Add to dashboard Cite

Guard cells must maintain the integrity of the plasma membrane as they undergo large, rapid changes in volume. It has been assumed that changes in volume are accompanied by changes in surface area, but mechanisms for regulating plasma membrane surface area have not been identified in intact guard cells, and the extent to which surface area of the guard cells changes with volume has never been determined. The alternative hypothesis-that surface area remains approximately constant because of changes in shape-has not been investigated. To address these questions, we determined surface area for intact guard cells of Vicia faba as they underwent changes in volume in response to changes in the external osmotic potential. We also estimated membrane internalization for these cells. Epidermal peels were subjected to external solutions of varying osmotic potential to shrink and swell the guard cells. A membrane-specific fluorescent dye was used to identify the plasma membrane, and confocal microscopy was used to acquire a series of optical paradermal sections of the guard cell pair at each osmotic potential. Solid digital objects representing the guard cells were created from the membrane outlines identified in these paradermal sections, and surface area, volume, and various linear dimensions were determined for these solid objects. Surface area decreased by as much as 40% when external osmotic potential was increased from 0 to 1.5 MPa, and surface area varied linearly with volume. Membrane internalization was approximated by determining the amount of the fluorescence in the cell's interior. This value was shown to increase approximately linearly with decreases in the cell's surface area. The changes in surface area, volume, and membrane internalization were reversible when the guard cells were returned to a buffer solution with an osmotic potential of approximately zero. The data show that intact guard cells undergo changes in surface area that are too large to be accommodated by plasma membrane stretching and shrinkage and suggest that membrane is reversibly internalized to maintain cell integrity.Guard cells regulate stomatal pore size to allow CO 2 uptake while controlling water loss. To accomplish this, they respond to environmental factors such as light and CO 2 concentration and to chemical signals such as ABA, which may originate in other parts of the plant. Guard cells respond to these factors by regulating ion fluxes across the plasma membrane, and the resulting movement of water causes changes in cell volume, turgor pressure, and shape, leading to changes in the pore aperture. The changes in guard cell turgor pressure and volume caused by these processes can be quite large. In Vicia faba, guard cell turgor pressure has been shown to vary between 1.0 and 4.0 MPa (Franks et al., 1998(Franks et al., , 2001) as stomata go from closed to wide open, and volume has been shown to change by as much as 40% (Raschke and Dickerson, 1973;Franks et al., 2001). These changes can occur over a time period of minutes.An often-un...

show abstract

“…The rationale for this approach is that stomatal aperture increases when guard cells expand in volume (Franks et al, 1995(Franks et al, , 1998 and that shifts in guard cell volume often result from osmotic water movements driven by active regulation of guard cell ion transport and carbon metabolism (note that guard cell water movements can also occur passively as a result of changes in local water potential). Guard cell volume, or turgor, is typically predicted from mass balance; that is, by assuming that water potential is dictated by a steady-state balance between water supply from elsewhere in the leaf or plant and evaporative water loss to the atmosphere.…”

Section: Process-based Modelingmentioning

confidence: 99%

Modeling Stomatal Conductance

2017

View full text Add to dashboard Cite

ORCID ID: 0000-0001-7610-7136 (T.N.B.).Robust models of stomatal conductance are greatly needed to predict plant-atmosphere interactions in a changing climate and to integrate new knowledge in physiology and ecological theory. Recent years have brought major advances in the experimental and theoretical understanding underpinning both processbased and optimality-based approaches to modeling stomatal function. I review these advances, highlight areas in need of more research, and argue that these modeling approaches are poised to supersede the long-dominant empirical approach.A reliable and general model for leaf stomatal conductance (g s ) has long been one of the holy grails of plant physiology. By controlling the exchange of water and carbon dioxide between plants and the atmosphere, stomata play a central role in the regulation of leaf and plant water status and transport, photosynthesis, drought sensitivity and tolerance, competition for soil resources, and even landscape and global hydrology (Hetherington and Woodward, 2003). An integrative formal theory-a mathematical model-that links stomatal function to plant traits and environmental variables would thus have incalculable value, both for making forward predictions and for drawing inferences about the physiology and ecology of observed stomatal behavior. My aim in this article is to summarize recent progress toward such models of stomatal conductance.Stomatal conductance has historically been predicted almost exclusively using empirical or phenomenological models, such as the widely used Jarvis and Ball-Berry families of models (Jarvis, 1976;Ball et al., 1987). Such models are perfectly adequate for forward prediction in situations where their parameters can be estimated with confidence, and indeed, these models continue to inform gas exchange projections across the modeling community (e.g. Oleson et al., 2008). However, the phenomenology of stomatal behavior in seed plants is by now very well established, so little further progress is likely in the area of empirical modeling, nor is it likely worth pursuing given that empirical models cannot provide insight about the underlying controls on gas exchange, but can only summarize and project what we already know about stomata. (Some aspects of the phenomenology of stomatal behavior in nonseed plants remain unresolved, such as the responses to CO 2 and abscisic acid [e.g. Brodribb and McAdam, 2011;Chater et al., 2011;Ruszala et al., 2011;Brodribb and McAdam, 2017]; empirical models have yet to be thoroughly validated for these taxa, so progress remains possible on that front.) This article will therefore focus on process-based ("mechanistic") and goaldirected ("optimality") approaches to predicting and interpreting stomatal function.In what follows, I will very briefly review the background to each of these approaches, describe important advances over the last decade or so, and then suggest directions for continuing work. I prefer to avoid reproducing equations and instead refer readers to articles cited here...

show abstract

Guard cell pressure/aperture characteristics measured with the pressure probe

Cited by 60 publications

References 16 publications

Pressure Regulation of the Electrical Properties of Growing Arabidopsis thaliana L. Root Hairs

Pressure Regulation of the Electrical Properties of Growing Arabidopsis thaliana L. Root Hairs

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

Modeling Stomatal Conductance

Contact Info

Product

Resources

About