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Ball tonometry: a rapid, nondestructive method for measuring cell turgor pressure in thin-walled plant cellsIn this article we describe a new method for the determination of turgor pressures in living plant cells. Based on the treatment of growing plant cells as thin-walled pressure vessels, we find that pressures can be accurately determined by observing and measuring the area of the contact patch formed when a spherical glass probe is lowered onto the cell surface with a known force. Within the limits we have described, we can show that the load (determined by precalibration of the device) divided by the projected area of the contact patch (determined by video microscopy) provides a direct, rapid, and accurate measure of the internal turgor pressure of the cell. We demonstrate, by parallel measurements with the pressure probe, that our method yields pressure data that are consistent with those from the pressure probe. Also, by incubating target tissues in stepped concentrations of mannitol to incrementally reduce the turgor pressure, we show that the pressures measured by tonometry accurately reflect the predicted changes from the osmotic potential of the bathing medium. The advantages of this new method over the pressure probe are considerable, however, in that we can move rapidly from cell to cell, taking measurements every 20 s. In addition, the nondestructive nature of the method means that we can return to the same cell repeatedly for periodic pressure measurements. The limitations of the method lie in the fact that it is suitable only for superficial cells that are directly accessible to the probe and to cells that are relatively thin walled and not heavily decorated with surface features. It is also not suitable for measuring pressures in flaccid cells.
Document ID
20040112735
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Lintilhac, P. M.
(The University of Vermont Burlington 05405, United States)
Wei, C.
Tanguay, J. J.
Outwater, J. O.
Date Acquired
August 21, 2013
Publication Date
March 1, 2000
Publication Information
Publication: Journal of plant growth regulation
Volume: 19
Issue: 1
ISSN: 0721-7595
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: 2399-0042
CONTRACT_GRANT: NAGW-3604
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center

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