Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Hejnowicz, Z.
Right arrow Articles by Sievers, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Hejnowicz, Z.
Right arrow Articles by Sievers, A.
Agricola
Right arrow Articles by Hejnowicz, Z.
Right arrow Articles by Sievers, A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 1995 Oxford University Press

RESEARCH-ARTICLE

Tissue 81

Zygmunt Hejnowicz and Andreas Sievers2

Botanisches Institut, Universität Bonn Venusbergweg 22, D-53115 Bonn, Germany

2To whom correspondence should be addressed. Fax: +49 228 732677.

Tissue stress (TS) is defined as the stress which acts on a tissue layer in an organ in excess of the turgor-induced tensile stress which also acts on the layer when it is isolated from the organ. The tensile TS in one layer of an organ is always accompanied by com-pressive TS in another layer. To calculate TS from data obtained for isolated tissue, one needs to know the Poisson ratios

VIKcontraction in the k-direction/extension in the i-direction

for the tensile force applied in the i-direction for that tissue. Poisson ratios apply in the relationships between (i) tissue extensions caused by uniaxial stress (due to applied force) and multiaxial stress (due to turgor pressure); (ii) extensions of tissues subjected to lateral constraint, and (iii) TSs in different directions. The ratios VIW and VWI, for the stress applied either longitudinally (I) or in the direction of width (W), respectively, were determined for the outer tissue (OT) of sunflower hypocotyls, tulip leaves and tulip stems. The two ratios for a particular OT differed considerably. The ratios depended on the applied extension (strain). Knowing them, the tensile force (F1) generating TS in the OT of an intact organ could be calculated from the longitudinal force (FI(s)) which when applied to the isolated (unconstrained laterally) OT restored its original length. In the case of the sunflower hypocotyls, FI(s)<F1<1.3 ×FI(s). The ratio VIr (r denotes the radial direction), which was determined for segments of inner tissue, from sunflower hypocotyls and tulip stems, did not depend on the applied stress (extension). This ratio allowed us to calculate the relationship between the strain changes caused by equal changes of uniaxial and multiaxial stresses: the uniaxial stress was approximately 3-fold more efficient than the multiaxial stress.

Key words: Elastic strains, Poisson ratios, tissue stresses, tissue elasticity, uni- and multiaxial stresses.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Am. J. Bot.Home page
P. Schopfer
Biomechanics of plant growth
Am. J. Botany, October 1, 2006; 93(10): 1415 - 1425.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
D.S. Thompson
Extensiometric determination of the rheological properties of the epidermis of growing tomato fruit
J. Exp. Bot., June 1, 2001; 52(359): 1291 - 1301.
[Abstract] [Full Text] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.