Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- 1 Global change and plant water relations
- 2 Cavitation. A review: past, present and future
- 3 Effect of cavitation on the status of water in plants
- 4 Stomatal control of xylem cavitation
- 5 Refilling of embolized xylem
- 6 Interpretation of the dynamics of plant water potential
- 7 A proposed mechanism of freezing and thawing in conifer xylem
- 8 Winter xylem embolism and spring recovery in Betula cordifolia, Fagus grandifolia, Abies balsamea and Picea rubens
- 9 Drought resistance strategies and vulnerability to cavitation of some Mediterranean sclerophyllous trees
- 10 Relations between sap velocity and cavitation in broad-leaved trees
- 11 NMR and water transport in plants
- 12 The symplast radial-axial water transport in plants: a NMR approach
- 13 Reproductive adaptation by polyembryony of coniferous forest trees under climatic stress as revealed by the metabolism of tritiated water
- 14 A heat balance method for measuring sap flow in small trees
- 15 Heat pulse measurements on beech (Fagus sylvatica L.) in relation to weather conditions
- 16 Extremely fast changes of xylem water flow rate in tall trees caused by atmospheric, soil and mechanic factors
- 17 Water relations and water transport in coppice vs. single stem Quercus cerris L. trees
- 18 Environmental control of water flux through Maritime pine (Pinus pinaster Ait).
- 19 Evaluation of transpiration of apple trees and measurement of daily course of water flow within the main branches of walnut trees
- 20 Estimating citrus orchard canopy resistance from measurements of actual and potential transpiration
- 21 Stomatal conductance in tomato responds to air humidity
- 22 Water relations of Canarian laurel forest trees
- 23 Watering regime and photosynthetic performance of Gunnera tinctoria (Molina) Mirbel.
- 24 Water relations and ultrasound emissions in Douglas-fir seedlings infected with xylem pathogens
- 25 Diurnal fruit shrinkage: a model
- 26 Analysis of pressure-volume curves by non-linear regression
- 27 Determination of the amount of apoplastic water and other water relations parameters in conifer needles
- 28 The assessment of water status in chilled plants
- 29 An artificial osmotic cell: a model system for studying phenomena of negative pressure and for determining concentrations of solutes
- 30 Measurement of water and solute uptake into excised roots at positive and negative root pressures
- Index
3 - Effect of cavitation on the status of water in plants
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- List of contributors
- Preface
- 1 Global change and plant water relations
- 2 Cavitation. A review: past, present and future
- 3 Effect of cavitation on the status of water in plants
- 4 Stomatal control of xylem cavitation
- 5 Refilling of embolized xylem
- 6 Interpretation of the dynamics of plant water potential
- 7 A proposed mechanism of freezing and thawing in conifer xylem
- 8 Winter xylem embolism and spring recovery in Betula cordifolia, Fagus grandifolia, Abies balsamea and Picea rubens
- 9 Drought resistance strategies and vulnerability to cavitation of some Mediterranean sclerophyllous trees
- 10 Relations between sap velocity and cavitation in broad-leaved trees
- 11 NMR and water transport in plants
- 12 The symplast radial-axial water transport in plants: a NMR approach
- 13 Reproductive adaptation by polyembryony of coniferous forest trees under climatic stress as revealed by the metabolism of tritiated water
- 14 A heat balance method for measuring sap flow in small trees
- 15 Heat pulse measurements on beech (Fagus sylvatica L.) in relation to weather conditions
- 16 Extremely fast changes of xylem water flow rate in tall trees caused by atmospheric, soil and mechanic factors
- 17 Water relations and water transport in coppice vs. single stem Quercus cerris L. trees
- 18 Environmental control of water flux through Maritime pine (Pinus pinaster Ait).
- 19 Evaluation of transpiration of apple trees and measurement of daily course of water flow within the main branches of walnut trees
- 20 Estimating citrus orchard canopy resistance from measurements of actual and potential transpiration
- 21 Stomatal conductance in tomato responds to air humidity
- 22 Water relations of Canarian laurel forest trees
- 23 Watering regime and photosynthetic performance of Gunnera tinctoria (Molina) Mirbel.
- 24 Water relations and ultrasound emissions in Douglas-fir seedlings infected with xylem pathogens
- 25 Diurnal fruit shrinkage: a model
- 26 Analysis of pressure-volume curves by non-linear regression
- 27 Determination of the amount of apoplastic water and other water relations parameters in conifer needles
- 28 The assessment of water status in chilled plants
- 29 An artificial osmotic cell: a model system for studying phenomena of negative pressure and for determining concentrations of solutes
- 30 Measurement of water and solute uptake into excised roots at positive and negative root pressures
- Index
Summary
SUMMARY
Negative turgor pressures must develop not only in the xylem but also in leaf cells when the moisture stress reaches a certain level. Since the pressure external to plant organs is atmospheric, cells containing liquids at negative pressures are exposed to a compressive stress and will collapse if the stress exceeds a critical limit. Water at negative turgor pressures is metastable and cavities filled with air should be formed either through bubble formation or through air entry through pores. If the pressure in the liquid drops below the vapour pressure of water, the liquid becomes unstable with respect to the formation of bubbles that are filled with water vapour. Although the water is metastable, a change to the stable gaseous phase is hindered by a high “activation energy” due to the surface work required to create a bubble of a critical size. Cavitation should increase the water potential in plant tissues. In the xylem, this effect is overshadowed by a decrease in xylem conductivity resulting in a loss of foliar water potential. Deviations from the usual pressure-volume curves are interpreted to reflect gains in water potential.
INTRODUCTION
The cohesion theory as originally developed by Bohm in the 1880s (Bohm, 1893) and subsequently expanded by Askenasy (1895) and Dixon & Joly (1895) to explain the rise of sap in tall plants had to assume a metastable state of water that was difficult to reproduce in laboratory experiments. It was, therefore, not surprising that the theory was criticized, in particular by those scientists who had a thorough understanding of physics, and it was even insinuated that Bohm might be suffering from hallucinations.
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- Water Transport in Plants under Climatic Stress , pp. 27 - 40Publisher: Cambridge University PressPrint publication year: 1993
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