Document Detail


Cavitation fatigue and its reversal in sunflower (Helianthus annuus L.).
MedLine Citation:
PMID:  11971926     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
"Cavitation fatigue" is the increased susceptibility of a xylem conduit to cavitation as a result of its prior cavitation. It was investigated whether cavitation fatigue induced in vivo could be repaired in intact plants. Sunflowers (Helianthus annuus L.) were subjected to soil drought in the greenhouse. Native embolism and vulnerability to cavitation was measured in well-watered controls and after 5 d and 10 d of controlled drought. A dramatic cavitation fatigue was observed where droughted xylem that was refilled in the laboratory developed up to 60 PLC (percentage loss of hydraulic conductivity) at -1 MPa versus only 5.2 PLC in non-droughted controls. Rewatered plants showed the complete reversal of cavitation fatigue over 4 d. Reversal of fatigue was correlated with the refilling of embolized vessels in the intact plants (r(2)=0.91, P<0.01), suggesting that xylem transport to fatigued vessels was required for their repair. The in vivo reversal of fatigue was partially duplicated in excised stem segments by perfusing them with root exudates from droughted (DR) and well-watered (WW) plants. The DR exudate had a greater effect, and this was associated with a greater pH in the DR versus WW saps, but there was no difference in total cation concentration. Perfusions with 2 mM CaCl(2) and KCl solutions also partially reversed cavitation fatigue as opposed to no effect with deionized water, suggesting a role of ions in addition to a pH effect. It is suspected that fatigue is caused by stretching and partial disruption of linkages between cellulose microfibrils in inter-conduit pit membranes during air seeding, and that the reversal of fatigue involves restoring these linkages by ingredients in xylem sap.
Authors:
Volker Stiller; John S Sperry
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of experimental botany     Volume:  53     ISSN:  0022-0957     ISO Abbreviation:  J. Exp. Bot.     Publication Date:  2002 May 
Date Detail:
Created Date:  2002-04-24     Completed Date:  2002-07-22     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  9882906     Medline TA:  J Exp Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  1155-61     Citation Subset:  IM    
Affiliation:
Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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MeSH Terms
Descriptor/Qualifier:
Biological Transport / drug effects
Calcium Chloride / pharmacology
Disasters
Environment, Controlled
Helianthus / physiology*
Hydrogen-Ion Concentration
Plant Structures / physiology*
Potassium Chloride / pharmacology
Water / metabolism,  pharmacology*
Chemical
Reg. No./Substance:
10043-52-4/Calcium Chloride; 7447-40-7/Potassium Chloride; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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