Document Detail

Why Canny's theory doesn't hold water.
MedLine Citation:
PMID:  10449384     Owner:  NLM     Status:  In-Data-Review    
A critique of Martin Canny's theory of water transport supported by tissue pressure is given with reference to basic principles of cellular water relations and biomechanics. It is shown that the application of tissue pressure in Canny's theory is neither internally consistent nor compatible with basic biophysics. Canny's translation of tissue pressure into an altered steady-state pressure in the xylem conduits has no defensible mechanism, relying instead on untenable action-at-a-distance and poor definitions. Tissue pressure itself, as defined by Canny and illustrated by the example of a turgid leaf, may well exist. However, it cannot function in whole-plant processes as envisioned by Canny, nor can it exist in the magnitude his theory would require. Rigid outer tissue layers containing internal pressures of the magnitude postulated by Canny would require a tensile strength quite incompatible with the observed biological materials. A simple application of La Place's Law illustrates that this is an issue of scale and that the turgor generated by osmotic potentials must be balanced primarily at the cellular level, and not the tissue level.
J P Comstock
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  American journal of botany     Volume:  86     ISSN:  0002-9122     ISO Abbreviation:  Am. J. Bot.     Publication Date:  1999 Aug 
Date Detail:
Created Date:  2011-06-17     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370467     Medline TA:  Am J Bot     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1077-81     Citation Subset:  -    
Boyce Thompson Institute, Tower Road, Ithaca, New York 14853-1801.
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