awn

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Ear of corn with awns
Real feather grass ( Stipa pennata ), hairy awns

An awn (also Arista ) (from ahd. Grana , beard hair) is a bristle or thread-shaped, usually somewhat rigid extension of a plant organ. Awns can be straight, curved, kneeled or twisted, as well as branched, as is the case with the genus Aristida , hairy (for wind spread) or rough. In the latter case, they easily get stuck in the animal's fur, which promotes the spread.

They can be found, for example, on the back or at the end of the husks of many sweet grasses (Poaceae). The husk corresponds to the lower leaf, the awn is usually considered to be homologous to the leaf blade . But this is not undisputed. The longest awns have the feather grass ( Stipa ).

In grasses, the awn plays a role in photosynthesis as well as in water regulation and seed dispersal .

During threshing , the awns are removed from grain that is to be processed into grain products and together with pods, husks , seed coats and stalk parts form the chaff .

Common heron beak ( Erodium cicutarium ): Partial fruits with a screw-like awn

Another awn-like structure is found in the cranesbill family (Geraniaceae). The protracted fruits decompose at the maturity of five fruits each with a bristle-like appendage which the outer wall of the fruit sheet corresponds to, and is referred to as awn. In the Heron Beak ( Erodium ) genus , the awns move through swelling and swelling ( hygroscopic ) and in doing so, drill the seeds into the ground.

Awn-like tips can also be formed in leaves , as in some oak species or in the awn-rattle pot and cartilage . Awns are also sometimes used for the appendages of the anthers in the genus Erica and the seed extensions in Strophanthus seeds. A pappus of the daisy family can be designed grannenartig as the sunflower . The awn pine gets its name from the stiff, pointed and awn-like thorns of the cones. The cone scales of the related long-lived pine are also pointed like awning.

The stiff guard hair (line hair ) from the upper fur of many animals is also called awn for short.

Individual evidence

  1. ↑ Ann Fowler Rhoads, Timothy A. Block: The Plants of Pennsylvania: An Illustrated Manual. University of Pennsylvania Press, 2007, ISBN 978-0-8122-4003-0 , p. 364.
  2. ^ A b c Peter Sitte, Hubert Ziegler, Friedrich Ehrendorfer, Andreas Bresinsky: Strasburger, textbook of botany. Gustav Fischer, Stuttgart / Jena / New York, 1991, ISBN 3-437-20447-5 , p. 821.
  3. ↑ Bertold Heyden: Study of awn formation in wheat - in comparison with leaf growth. In: seeds. Communications Keyserlingk Institute, (No. 21, p. 13, 2007), see also No. 23, pp. 1–42, 2010. Keyserlingk Institute (PDF)
  4. ↑ awn (Arista). In: George P. Rédei: Encyclopedia of Genetics, Genomics, Proteomics and Informatics. Springer, 2008, ISBN 978-1-4020-6753-2 , p. 173, doi: 10.1007 / 978-1-4020-6754-9_1431 .
  5. ↑ Xing-feng Li, Du Bin, Wang Hong-gang: Awn anatomy of common wheat (Triticum aestivum L.) and its relatives. In: Caryologia. 63 (4), 2010, pp. 391-397, doi: 10.1080 / 00087114.2010.10589751 .
  6. ↑ Vernon H. Heywood (ed.): Flowering plants of the world. Birkhäuser, Basel / Boston / Stuttgart, 1982, ISBN 3-7643-1305-6 , p. 209.
  7. ^ A b Peter Sitte, Hubert Ziegler, Friedrich Ehrendorfer, Andreas Bresinsky: Strasburger, textbook of botany. Gustav Fischer, Stuttgart / Jena / New York, 1991, ISBN 3-437-20447-5 , p. 785.
  8. ↑ Michael Hickey, Clive King: The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press, 2000, ISBN 0-521-79401-3 , p. 4.
  9. ^ Robert Fischer, Theodor Kartnig: Drug Analysis. 5th edition, Springer, 1978, ISBN 978-3-211-82440-5 (reprint), p. 149.
  10. ^ Rothmaler - excursion flora from Germany. Volume 5, Springer, 2007, 2016, ISBN 978-3-662-50419-2 , pp. 544, 545, 551.
  11. ↑ The large Fischer Lexicon in color. Volume 7, Fischer, Frankfurt am Main, 1976, ISBN 3-436-02345-0 , p. 2435.

Web links

Wiktionary: Granne  - explanations of meanings, word origins, synonyms, translations