ISSN:
1432-2048
Keywords:
Blue light
;
Cell wall (relaxation, viscoelastic properties)
;
Cucumis (elongation growth)
;
Growth biophysics
;
Hypocotyl
;
Photomorphogenesis
;
Wall relaxation
;
Water relations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Rapid 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 vaporpressure osmometry, was not decreased by blue light; turgor pressure, measured by the pressureprobe 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00392486
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