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Column ( lat. Columna ), or gynostemia ( lat. Gynostemium ) - in botany : the part of the flower that is formed as a result of the accretion of androceum and gynoecium .
Sometimes the term “column” is used in botany and in other meanings - to name a part of a gynoceum or a part of a fetus .
Column as part of flower
Column formation, or gynostemia, a single reproductive organ, as a result of the intergrowth of androceum (male reproductive organ) and gynecium (female reproductive organ), is characteristic of plants from the Orchid ( Rafflesia ) and Rafflesia ( Rafflesia ) families .
In the most primitive orchids, the stamens (two or three) do not fully grow together with the post and stigma, and there are fairly large free areas. Representatives of the subfamily Tsipripediye free sites also exist, but they are very short. In the so-called single-tongued orchids, the column is a single elongated structure formed as a result of the accretion of a single stamen with a column and stigma . The shape of the column in a particular species is largely determined by the specificity of the pollination agent. [one]
Orchid Vanilla planifolia , flower structure: sepals (1, 2, 3); right petal (4); left petal removed; lip (5); boot (6); beak (7); stigma (8); column (9; its parts are also 6, 7, 8), ovules (10), ovary (11) | ||||||||||
In rafflesian, the column is massive, mushroom shaped. The top of the column has a larger diameter than its base; this extended part is called a disk . Usually the disk is abundantly covered with spines. Below the edges of the disk are the anthers , immersed in separated from each other grooves. Each anther consists of several nests, opening through apical pores. Insects - pollinators first fall on the disk, then fall down below, into the ring furrow, where the anthers are located. [2]
Rafflesia kerrii (flower diameter is about 60 cm. The surface, richly covered with spines, is the top of the column; the formation hanging over the column and partially closing it is an expanded perianth (the so-called diaphragm). | ||||||||||
Such reproductive combined organs are also found in representatives of the families of Kirkazonovye ( Aristolochiaceae ) and Stylidium ( Stylidiaceae ).
Orchid column structure
The column is a characteristic diagnostic sign of the orchid flower, which is an accrete stamen and pistil.
It includes the stigma of the surface, the anther , which is located in a special recess on its top (clinandria), rostellum (a sterile part of the stigma that separates it from the anther) and several (from 2 to 8) pollinia (glued pollen grains) that have special appendages (tegula | tegula, caudicula , viscidia ), which play an important role in pollination.
The base of the column is more or less long, usually downward or forward, the directed extension of the base of the column, to the top of which a lip is attached with its base [3] .
Stigma fossa - a recess lined with perceiving glandular tissue. It is formed by the merger of two fertile lobes of the stigma and immersion of the stigma in the fabric of the column [3] .
The beak , or Rostellum ( lat. Rostellum ), is a modified sterile tip of the medial portion of the stigma, usually acquiring a complex structure. Carries various functions, including interferes with self-pollination , participates in the formation of adhesives , tegulae , hamulus , bursiculae, etc., rarely completely reduced [3] .
Bursicula ( Latin bursicula ), pocket - a small membranous fold or cap, covering the sticky (sticky) in the flower of some representatives of the subtribe Orchidinae . Formed by the outer layer of cloth hook [3] .
Clynandrium ( lat. Clinandrium ) - anther bed, hemispherical hole at the top of the column, in which lie pollinia , covered with operculum . This dimple is bounded posteriorly by the base of the stamen, and laterally often by staminodes [3] .
Stelidia ( lat. Stelidia ) - pterygoid or finger-shaped appendages, located on the sides of the column, often at its top. [3] .
Stigmafors are more or less long, usually forward-directed outgrowths (stalks) of the column of some representatives of the subtribe Gymnadeniinae , bringing out both lobes of the stigma towards the intended pollinator [3] .
Column as part of the gynjeca.
The term “column” is also used to refer to the central part of a lysicard gynoecium ( single gynoia, formed by several accreted carpels ). The column is located in the center of the ovary , ovules form on the column. Such a structure of gynetsa is typical, for example, for representatives of the family of carnations ( Caryophyllaceae ).
Column as part of the fruit
The term “column” is also used to denote that part of a fractional fruit that persists after the fall of the mericarpies (fractional parts).
Notes
- ↑ Gladkova V.N. Orchid family (Orchidaceae) // Plant Life. In 6 t. / Ch. ed. A.L. Tahtajan . - M .: Enlightenment, 1981. - T. 6. Flowering plants. / Ed. A.L. Tahtajyan . - p. 248-275. - 543 s., Il .; 34 l. silt with. - 300 000 copies
- ↑ Rafflesia // Wikipedia. Free encyclopedia. [2008–]. Update date: 13.02.2009. URL: http://en.wikipedia.org/?oldid=13756630 (appeal date: 03/02/2009).
- ↑ 1 2 3 4 5 6 7 Averyanov L.V. Determinant of orchid trees of Vietnam. 1994.
Literature
- Korovkin OA Anatomy and morphology of higher plants: a glossary of terms. - M .: Drofa, 2007. - p. 55, 79, 94. - 268, [4] p. - (Biological sciences: Dictionaries of terms). - 3000 copies - ISBN 978-5-358-01214-1 .
Links
- Orchids // The Great Soviet Encyclopedia : [in 30 t.] / Ch. ed. A. M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.
- Gynostemia in the Botanical Terms Dictionary