Style (botany)

The style is a narrow extension of the ovary, usually pointing upwards, connecting the ovary to the stigmatic papillae. It may be absent in some plants; in this case, it is referred to as a sessile stigma. Styles generally resemble more or less long tubes. The style can be open (with few cells occupying the central part, or even none), featuring a central canal that may be filled with mucilage. Alternatively, the style can be closed (completely filled with cells). Most plants with syncarpous pistils (monocotyledons and some eudicotys) have open styles, whereas many eudicots and grasses have closed (solid) styles containing specialized secretory tissues, which connect the stigma to the center of the ovary. These tissues form a nutrient-rich cord for the growth of the pollen tube.{{sfn|Rudall|2007}}

When the pistil consists of several carpels, each of them may have a distinct stylodium (sometimes seen as a pseudo-style{{Cite journal |last=Sokoloff |first=Dmitry D. |last2=Remizowa |first2=Margarita V. |last3=Linder |first3=H. Peter |last4=Rudall |first4=Paula J. |date=2009 |title=Morphology and development of the gynoecium in Centrolepidaceae: The most remarkable range of variation in Poales |url=https://www.zora.uzh.ch/id/eprint/27898/11/Sokoloff_AJB_2009_V.pdf |journal=American Journal of Botany |language=en |volume=96 |issue=11 |pages=1925–1940 |doi=10.3732/ajb.0900074 |issn=0002-9122}}) or share a common style. In Iris and other species of the Iridaceae family, the style divides into three "petaloid branches" (resembling petals), sometimes also called stylodiums,{{sfn|Rudall|2007}} almost at the origin of the style and is called "tribrachiate". These are strips of tissue emerging from the perianth tube above the sepal. The stigma is a ridge or edge on the lower surface of the branch, near the tip of the lobes.{{cite web |access-date=27 July 2015 |language=en |publisher=herbs2000.com |title=The Anatomy of Irises |url=http://www.herbs2000.com/flowers/i_anatomy.htm}}. Branched styles also appear in the genera Dietes, Pardanthopsis, and in most species of the genus Moraea.{{cite book |editor-first1 =Klaus |editor-last1 = Kubitzki | first1= H. | last1=Huber | first2 = P.J. | last2 = Rudall |first3 = P.S. | last3 = Stevens | first4 = T. |last4 = Stützel |date=2013 |isbn=978-3-662-03533-7 |language=en |page=305 |publisher=Springer Science & Business Media |series=The Families and Genera of Vascular Plants |title=Flowering Plants. Dicotyledons : Celastrales, Oxalidales, Rosales, Cornales and Ericales |url=https://books.google.com/books?id=RSfrCAAAQBAJ}}

In Crocus species, the style is branched into three "branches," forming a tube.{{cite book |first1=Michael | last1 = Hickey |first2=Clive |last2 = King |date=1988 |isbn=978-0-521-33700-7 |language=en |page=562 |publisher=Cambridge University Press |title=100 Families of Flowering Plants |url=https://books.google.com/books?id=LDh7fz9uToMC}} Plants of the genus Hesperantha have a spread-out branched style. The style can also be lobed rather than branched. Plants of the genus Gladiolus have a bilobed style. In the genera Freesia, Lapeirousia, Romulea, Savannosiphon, and Watsonia, the style has bifurcated and curved branches.{{cite book |editor-first1 =Klaus |editor-last1 = Kubitzki | first1= H. | last1=Huber | first2 = P.J. | last2 = Rudall |first3 = P.S. | last3 = Stevens | first4 = T. |last4 = Stützel |date=2013 |isbn=978-3-662-03533-7 |language=en |page=305 |publisher=Springer Science & Business Media |series=The Families and Genera of Vascular Plants |title=Flowering Plants. Dicotyledons : Celastrales, Oxalidales, Rosales, Cornales and Ericales |url=https://books.google.com/books?id=RSfrCAAAQBAJ}}{{cite book |editor-first1 =Klaus |editor-last1 = Kubitzki | first1= H. | last1=Huber | first2 = P.J. | last2 = Rudall |first3 = P.S. | last3 = Stevens | first4 = T. |last4 = Stützel |date=2013 |isbn=978-3-662-03533-7 |language=en |page=305 |publisher=Springer Science & Business Media |series=The Families and Genera of Vascular Plants |title=Flowering Plants. Dicotyledons : Celastrales, Oxalidales, Rosales, Cornales and Ericales |url=https://books.google.com/books?id=RSfrCAAAQBAJ}}

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| image3 = Saffron stigmas Crocus speciosus corrected cropped.jpg

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| caption3 = {{center|The feathery stigma of Iris versicolor (Crocus speciosus) has three branches corresponding to the three carpels.}}

| image2 = Iris missouriensis (3624887687).jpg

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| caption2 = {{center|Flower of Iris missouriensis showing the light blue branched style above the drooping petal.}}

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| caption1 = {{center|Flower of the Iris versicolor showing three overlapping two-lipped structures, an upper petaloid branching, and a lower tepal, enclosing a stamen.}}

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| image1 = Gynoecium morphology style position terminal.png

| caption1 = Terminal (apical)

| image2 = Gynoecium morphology style position lateral.png

| caption2 = Lateral

| image3 = Gynoecium morphology style position gynobasic.png

| caption3 = Gynobasic

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May be terminal (apical), subapical, lateral, gynobasic, or {{notatypo|subgynobasic}}. Terminal (apical) style position refers to attachment at the apex of the ovary and is the most common pattern. In the subapical pattern, the style arises to the side slightly below the apex. A lateral style arises from the side of the ovary and is found in Rosaceae. The gynobasic style arises from the base of the ovary, or between the ovary lobes and is characteristic of Boraginaceae. {{notatypo|Subgynobasic}} styles characterise Allium.{{harvnb|Simpson|2011|loc=[https://books.google.com/books?id=Ia2eIPVksMMC&pg=PA378 Style position p. 378]}}

Pollen tubes grow the length of the style to reach the ovules, and in some cases self-incompatibility reactions in the style prevent full growth of the pollen tubes. In some species, including Gasteria at least, the pollen tube is directed to the micropyle of the ovule by the style.Christophe Clement, Ettore Pacini, Jean-Claude Audran (Editors) {{Googlebooks|TOXwCAAAQBAJ|Anther and Pollen: From Biology to Biotechnology|page=151}}

{{reflist}}

• {{cite book | last=Rudall | first=P.J. | title=Anatomy of Flowering Plants: An Introduction to Structure and Development | publisher=Cambridge University Press | year=2007 | isbn=978-1-139-45948-8 | url=https://books.google.com/books?id=cSO8HOKyabgC | access-date=2024-05-06}}
• {{cite book |last=Simpson|first=Michael G.|title=Plant Systematics|year=2011|publisher=Academic Press|isbn=978-0-08-051404-8|url=https://books.google.com/books?id=Ia2eIPVksMMC}}

Category:Plant reproduction

Category:Plant morphology