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Tendril perversion is a geometric phenomenon sometimes observed in
Tendril perversion is a geometric phenomenon sometimes observed in helical
Helical may refer to:
* Helix
A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is ...
structures in which the direction of the helix transitions between left-handed and right-handed. Such a reversal of chirality
Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object.
An object or a system is ''chiral'' if it is distinguishable from i ...
is commonly seen in helical plant tendril
In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape used by climbing plants for support and attachment, as well as cellular invasion by parasitic plants such as '' Cuscuta''. There are many plants that have ten ...
s and telephone handset cords.
The phenomenon was known to Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all speci ...
, who wrote in 1865,
The term "tendril perversion" was coined by Alain Goriely and Michael Tabor in 1998 based on the word ''perversion'' found in the 19th century science literature. "Perversion" is a transition from one chirality to another and was known to James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and ligh ...
, who attributed it to topologist J. B. Listing.
Tendril perversion can be viewed as an example of spontaneous symmetry breaking
Spontaneous symmetry breaking is a spontaneous process of symmetry breaking, by which a physical system in a symmetric state spontaneously ends up in an asymmetric state. In particular, it can describe systems where the equations of motion or ...
, in which the strained structure of the tendril adopts a configuration of minimum energy while preserving zero overall twist.
Tendril perversion has been studied both experimentally and theoretically. Gerbode et al. have made experimental studies of the coiling of cucumber
Cucumber (''Cucumis sativus'') is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as culinary vegetables.
Generalized tendril perversions were put forward by Silva et al., to include perversions that can be intrinsically produced in elastic filaments, leading to a multiplicity of geometries and dynamical properties.
A close-up image of a tendril perversion in a tendril of ''Bryonia dioica'' by Michael Becker
Helices Curves Chirality Symmetry
See also
* Helical growth *Hemihelix
A hemihelix is a curved geometric shape consisting of a series of helices with alternating chirality, connected by a perversion
Perversion is a form of human behavior which deviates from what is considered to be orthodox or normal. Although ...
References
External links
* {{Commons category-inlineA close-up image of a tendril perversion in a tendril of ''Bryonia dioica'' by Michael Becker
Helices Curves Chirality Symmetry