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
30 - Measurement of water and solute uptake into excised roots at positive and negative root pressures
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
INTRODUCTION
Transport properties of roots have been characterized by certain transport coefficients such as the hydraulic conductivity (LPr), the permeability (Psr), and reflection coefficient (σsr). So far, these coefficients have been measured only at positive root pressures. However, according to the cohesion theory of the ascent of sap, negative pressures exist in the xylem of transpiring plants. Therefore, it is of some interest whether or not the absolute values of the transport coefficients would change when pressures in the xylem drop to negative values, i.e. below vacuum (= 0 MPa).
In the present work, LPr, Psr σsr and asr of excised roots of Zea mays L. have been measured at positive and negative root pressures with the aid of the root pressure probe. Furthermore, responses of xylem pressures of intact maize plants to changes in the rate of transpiration have been followed directly.
MATERIALS AND METHODS
The hydrostatic hydraulic conductivity (LPrh) of root endsegments was determined with the aid of a root pressure probe. In ‘hydrostatic experiments’ a metal rod was moved into (out of) the probe and hence, root pressure was changed. LPrh was calculated from the following relaxation of root pressure (Steudle, Oren & Schulze, 1987). Alternatively, in ‘osmotic experiments’ the concentration of a solute in the medium was changed and LPr, Psr, and σsr were determined from the pressure responses (Steudle et al., 1987). The addition of a nonpermeating solute (mannitol) caused the root pressure to drop to a stationary negative pressure. Now, a permeating solute (Ethanol, NaNO3) was added or removed from the medium and again, LPr, Psr and σsr were calculated from root pressure responses.
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- Water Transport in Plants under Climatic Stress , pp. 293 - 294Publisher: Cambridge University PressPrint publication year: 1993