Pollinium

Fly ragwort ( Ophrys insectifera ) with easily visible pollinia

Broad-leaved stendellum - the stigma is clearly visible, above it the glutinous gland and the pollinia protruding from under the anther cap

Pollinia of an orchid of the genus Phalaenopsis

The pollinium (plural pollinia or Latin pollinia ) is a mostly sticky pollen mass , a pollen package as it is formed in particular by the stamens of orchids and silk plants to bloom.

The unit of pollinium, pollinia and mostly a stalk (caudicle and / or stipe, tegula, hamulus) and, in many species, one or two adhesive discs (viscidium), is called pollinarium in orchids . In some species the Viscidium lies in a pocket, cover sheet (Thecum, Bursicle).

In the silk plant family, two pollinia are attached to the corpusculum (clamp body, gland) with a stalk (caudicle) and additionally with the pollen holder (retinaculum), together the translator arm. The two translator arms and the corpusculum together form the translator . In the stapel , the stalk and the pelvis wing and the corpusculum form the translator. In some cases, the attachment of the stalk takes place in the middle section of the petiole wing, while in other cases it is directly on the corpusculum.

The pollinium enables effective pollination by insects, which are attracted by clever tricks. Some orchids lure their pollinators with nectar, while others only simulate a supply of nectar. Still others offer sleeping places for small insects, and the ragwort flowers even lure with sexual stimuli (sexual attractants , optical and tactile key stimuli). When visiting the flower, the insect is stuck with a pollen packet so that it can be precisely placed on the stigma when visiting the next flower. Some orchids, such as the Catasetum species, have a special slinging mechanism in which the bees trigger a slinging movement (explosion mechanism) in the flower by means of a lever and the pollinia are glued to the bee.

However, rare self-pollination is also possible here, with the orchid species Holcoglossum amesianum the pollinium moves independently to the fertile stigma in the columna .

literature

Spectrum Lexicon of Biology on CD-ROM. Spektrum-Verlag, Heidelberg 2003.
Marco Klüber: Orchids in the Rhön and their habitats protect - care - preserve (PDF), accessed on June 28, 2016.
Karen L. Wilson, David A. Morrison: Monocots. CSIRO, 2000, ISBN 0-643-06437-0 , pp. 296-299.

Web links

Commons : Pollinium - album with pictures, videos and audio files

Individual evidence

↑ RMT Dahlgren, HT Clifford, PF Yeo: The Families of the Monocotyledons. Springer, 1985, ISBN 978-3-642-64903-5 , p. 257, limited preview in the Google book search.
↑ M. Hesse, A. Dafni, E. Pacini: Pollen and Pollination. Springer, 2000, ISBN 3-211-83514-8 , pp. 243-252.
↑ Gerald S. Barad: Pollination of Stapeliads. In: Cactus and Succulent Journal. (US), Vol. 62 (3), 1990, pp. 130-140, online at cactus-mall.com, accessed December 30, 2017.
↑ Ke-Wei Liu, Zhong-Jian Liu et al .: Pollination: Self-fertilization strategy in an orchid. In: Nature. Vol. 441, 2006, pp. 945–46, doi : 10.1038 / 441945a , Orchidee mates on scienceticker.info, accessed on December 31, 2017.

[1] RMT Dahlgren, HT Clifford, PF Yeo: The Families of the Monocotyledons. Springer, 1985, ISBN 978-3-642-64903-5 , p. 257, limited preview in the Google book search.

[2] M. Hesse, A. Dafni, E. Pacini: Pollen and Pollination. Springer, 2000, ISBN 3-211-83514-8 , pp. 243-252.

[3] Gerald S. Barad: Pollination of Stapeliads. In: Cactus and Succulent Journal. (US), Vol. 62 (3), 1990, pp. 130-140, online at cactus-mall.com, accessed December 30, 2017.

[4] Ke-Wei Liu, Zhong-Jian Liu et al .: Pollination: Self-fertilization strategy in an orchid. In: Nature. Vol. 441, 2006, pp. 945–46, doi : 10.1038 / 441945a , Orchidee mates on scienceticker.info, accessed on December 31, 2017.