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Mechanism of rapid suppression of cell expansion in cucumber hypocotyls after blue-light irradiationRapid suppression of hypocotyl elongation by blue light in cucumber (Cucumis sativus L.) was studied to examine possible hydraulic and wall changes responsible for diminished growth. Cell-sap osmotic pressure, measured by vapor-pressure osmometry, was not decreased by blue light; turgor pressure, measured by the pressure-probe technique, remained constant during the growth inhibition; and stem hydraulic conductance, measured by dynamic and static methods, was likewise unaffected by blue light. Wall yielding properties were assessed by the pressure-block technique for in-vivo stress relaxation. Blue light reduced the initial rate of relaxation by 77%, but had little effect on the final amount of relaxation. The results demonstrate that blue irradiation acts to decrease the wall yielding coefficient, but not the yield threshold. Stress-strain (Instron) analysis showed that irradiation of the seedlings had little effect on the mechanical extensibilities of the isolated wall. The results indicate that blue light can reduce cell-wall loosening without affecting bulk viscoelastic properties, and indicate a chemorheological mechanism of cell-wall expansion.
Document ID
20040089573
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Cosgrove, D. J.
(University Park 16802 United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Planta
Volume: 176
ISSN: 0032-0935
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: DMB-8351030
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 40-30
NASA Discipline Plant Biology
Non-NASA Center
NASA Program Space Biology

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