The essentials of direct xylem pressure measurement

@article{Wei2001TheEO,
  title={The essentials of direct xylem pressure measurement},
  author={Chunfang Wei and Ernst Steudle and Melvin T. Tyree and Philip M. Lintilhac},
  journal={Plant Cell and Environment},
  year={2001},
  volume={24},
  pages={549-555}
}
This paper discusses the essentials of the oil-filled pressure probe technique in the measurement of negative xylem pressures, focusing in particular on the technique and physics underlying our recent, successful experiment which has rekindled the debate on the validity of the Cohesion–Tension theory. We illustrate a number of general problems associated with the cell pressure probe and xylem pressure probe techniques, and propose appropriate criteria for micropipette construction. We enumerate… 

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References

SHOWING 1-10 OF 28 REFERENCES
Direct measurement of xylem pressure in leaves of intact maize plants. A test of the cohesion-tension theory taking hydraulic architecture into consideration
TLDR
The hydraulic architecture model could predict all observed changes in water flow rate and xylem and measured the cavitation threshold for oil- and water-filled pressure probes and provide some suggestions for improvement.
Water ascent in plants: do ongoing controversies have a sound basis?
Mechanisms of long-distance water transport in plants: a re-examination of some paradigms in the light of new evidence
According to the widely accepted Cohesion Theory, water is pulled by transpiration from the roots through the xylem to the leaves. It is believed that this process results in the development of large
Short communication. Comparative measurements of xylem pressure in transpiring and non-transpiring leaves by means of the pressure chamber and the xylem pressure probe
proposed more than 100 years ago by Dixon and Joly (1894). According to this theory, long-distance water Simultaneous measurements were made with the transport in xylem is driven by tension (negative
High Molecular Weight Organic Compounds in the Xylem Sap of Mangroves: Implications for Long‐Distance Water Transport
The rise of sap in mangroves has puzzled plant physiologists for many decades. The current consensus is that negative pressures in the xylem exist which are sufficiently high to exceed the osmotic
Sap Pressure in Vascular Plants
TLDR
A method is described which permits measurement of sap pressure in the xylem of vascular plants, and finds that in tall conifers there is a hydrostatic pressure gradient that closely corresponds to the height and seems surprisingly little influenced by the intensity of transpiration.
Ultrasonic acoustic emissions from the sapwood of cedar and hemlock : an examination of three hypotheses regarding cavitations.
Measurements are reported of ultrasonic acoustic emissions (AEs) measured from sapwood samples of Thuja occidentalis L. and Tsuga canadensis (L.) Carr. during air dehydration. The measurements were
Growth Physics in Nitella: a Method for Continuous in Vivo Analysis of Extensibility Based on a Micro-manometer Technique for Turgor Pressure.
TLDR
Over long periods of treatment in a variety of osmotica the threshold value for extensibility and growth is seen to fall to lower values to permit resumption of growth at reduced turgor.
Water Relations and Hydraulic Architecture of a Tropical
TLDR
It is argued here that the high stem capacitance and high leaf-specific conductivity of Schefflera are necessary to compensate for its high vulnerability to cavitation.
Design of Two-Dimensional Wind Tunnel Contractions
Design charts for 2-D wind tunnel contractions have been developed using inviscid flow analysis, in which a one-parameter family of wall shapes, based on two cubic arcs, was investigated in detail.
...
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