Aril

Aril of a yew tree ( Taxus baccata )

Common spindle bush , euonymus europaeus , from the fruits hang seeds with orange aril.

An aril or seed coat is usually a fleshy, often colored shell that completely or partially covers a seed . It develops from a ring around the funiculus , the stem of the ovule . A colored aril is mostly used to attract animals that eat the aril and its seeds and thus serve to spread ( zoochory ).

A false seed coat (arillode) develops from parts of the ovule other than elaiosome . In euphorbias , the micropyle area , the exostome , is fleshy - this form is called the caruncula or exostomarillus.

A pseudo- arillus (pseudaril) is also possible , here in stone fruits a spongy tissue, starting from the mesocarp , is formed around the stone core. In some species, the aril is also interpreted as a remnant of a sarcotesta .

Examples

Aril formation occurs in some families of the coniferous plants (Pinophyta): yew plants (Taxaceae), stone holly plants (Podocarpaceae) and head yew plants (Cephalotaxaceae). Among the yew trees ( Taxus ), the aril is the only part that is non-toxic to humans, it does not contain any taxine . Even when ephedra ( Ephedra ) there is an aril.

Arilus formations occur sporadically in the cover-seeded plants and can be differently pronounced. Examples are:

In the spindle bushes ( Euonymus ), the aril completely encloses the seeds.
In the case of the nutmeg ( Myristica fragrans ), the arillus macis or mace is called and is torn.
In the water lilies ( Nymphaea ), the aril is designed as an air-containing sac and serves as a swim bladder.
The whitish pulp of litchi , mangosteen , longan and the yellowish pulp of durian consumed as fruit are arilli.

In a few species such as B. at the Monimia in the family Monimiaceae and Siparuna from the family of siparunaceae a arillusähnliche structure on the carpels formed and not in the seed. These trainings are also known as carpellary aril , stylar aril or superaril .

literature

Gerhard Wagenitz : Dictionary of botany. The terms in their historical context . 2nd expanded edition. Spectrum Academic Publishing House, Heidelberg / Berlin 2003, ISBN 3-8274-1398-2 .
Peter Sitte , Elmar Weiler , Joachim W. Kadereit , Andreas Bresinsky , Christian Körner : Textbook of botany for universities . Founded by Eduard Strasburger . 35th edition. Spektrum Akademischer Verlag, Heidelberg 2002, ISBN 3-8274-1010-X .

Web links

Commons : Arillus - collection of images, videos and audio files

Individual evidence

↑ ^a ^b L. van der Pijl : Principles of Dispersal in Higher Plants. 3rd edition, Springer, 1982, ISBN 978-3-642-87927-2 (reprint), p. 140.
↑ María F. Ramos-Ordoñez, M. del Coro Arizmendi et al .: The pseudaril of Bursera and Commiphora, a foretold homology? In: Revista Mexicana de Biodiversidad. Volume 84, Issue 2, 2013, pp. 509-520, doi : 10.7550 / rmb.32114 .
^ Sylvia R. Silveira, Marcelo C. Dornelas, Adriana P. Martinelli: Perspectives for a Framework to Understand Aril Initiation and Development. In: Frontiers in Plant Science. 7, 2016, p. 1919, doi : 10.3389 / fpls.2016.01919 .
↑ Susanne S. Renner, Gerlinde Hausner: In: Flora Neotropica. Vol. 95, Siparunaceae , 2005, pp. 1-247, at pp. 22, 139.

[Pijl-1] L. van der Pijl : Principles of Dispersal in Higher Plants. 3rd edition, Springer, 1982, ISBN 978-3-642-87927-2 (reprint), p. 140.

[2] María F. Ramos-Ordoñez, M. del Coro Arizmendi et al .: The pseudaril of Bursera and Commiphora, a foretold homology? In: Revista Mexicana de Biodiversidad. Volume 84, Issue 2, 2013, pp. 509-520, doi : 10.7550 / rmb.32114 .

[3] Sylvia R. Silveira, Marcelo C. Dornelas, Adriana P. Martinelli: Perspectives for a Framework to Understand Aril Initiation and Development. In: Frontiers in Plant Science. 7, 2016, p. 1919, doi : 10.3389 / fpls.2016.01919 .

[4] Susanne S. Renner, Gerlinde Hausner: In: Flora Neotropica. Vol. 95, Siparunaceae , 2005, pp. 1-247, at pp. 22, 139.