HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

What's this?

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Silk, W. K. Articles by Holbrook, N. M. Search for Related Content PubMed Articles by Silk, W. K. Articles by Holbrook, N. M. Agricola Articles by Silk, W. K. Articles by Holbrook, N. M. Social Bookmarking                            What's this?

The importance of frictional interactions in maintaining the stability of the twining habit¹

²Department of Land, Air, and Water Resources, University of California, Davis, California 95616-8627 USA; ³Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 USA

ABSTRACT

The stability of twining vines under gravitational loads suggests an important role for friction. The coefficient of friction, µ, between vine stems and wood is high, often five times greater than between leather and wood, as determined by slip tests on an inclined plane. Stem trichomes function like ratchets to facilitate climbing upward (or to facilitate slipping if the stem is inverted). A mathematical model predicts large masses (kg) must be applied to the base of a twining vine to cause slipping. Vines slip as predicted when µ is low and arc length on the pole is short, and they break before slipping when µ is large or arc length is long. In contrast, twining vines are unstable in compression, collapsing when small masses (<10 g) are hung from the top of the vine. However, if the loads are applied below the uppermost gyre, the stabilizing tensional effect dominates. Therefore, in nature vines twining on a cylindrical support are stable under gravitational loads, unless these loads occur near the apex. A corollary is that a short apical coil can hold up large masses of maturing shoot.

Key Words: biomechanics • curvature • friction • helix • Ipomoea purpurea • structural stability • twining • vines

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. Isnard, A. R. Cobb, N.M. Holbrook, M. Zwieniecki, and J. Dumais Tensioning the helix: a mechanism for force generation in twining plants Proc R Soc B, July 22, 2009; 276(1667): 2643 - 2650. [Abstract] [Full Text] [PDF]

				S. Isnard and W. K. Silk Moving with climbing plants from Charles Darwin's time into the 21st century Am. J. Botany, July 1, 2009; 96(7): 1205 - 1221. [Abstract] [Full Text] [PDF]

				A. J. Bowling and K. C. Vaughn Gelatinous fibers are widespread in coiling tendrils and twining vines Am. J. Botany, April 1, 2009; 96(4): 719 - 727. [Abstract] [Full Text] [PDF]