In botany, the petiole (/ˈpiːti.oʊl/) is the stalk that attaches the leaf blade to the stem,[1]: 87 [2]: 171 and is able to twist the leaf to face the sun. This gives a characteristic foliage arrangement to the plant.[3] Outgrowths appearing on each side of the petiole in some species are called stipules. Leaves with a petiole are said to be petiolate, while leaves lacking a petiole are called sessile or apetiolate.[citation needed]
Leaf of dog rose (Rosa canina), showing the petiole, two leafy stipules, the rachis, and five leaflets
Pulvina at both ends of the petiole. Elaeocarpus multiflorus
The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the leaf stalk may be long, as in the leaves of celery and rhubarb, or short. When completely absent, the blade attaches directly to the stem and is said to be sessile. Subpetiolate leaves have an extremely short petiole, and may appear sessile.[2]: 157 The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile.[4]: 639 In some other plant groups, such as the speedwell genus Veronica, petiolate and sessile leaves may occur in different species.[4]: 584
In the grasses (Poaceae), the leaves are apetiolate, but the leaf blade may be narrowed at the junction with the leaf sheath to form a pseudopetiole, as in Pseudosasa japonica.[5]: 391
In plants with compound leaves, the leaflets are attached to a continuation of the petiole called the rachis.[1]: 98 Each leaflet may be attached to the rachis by a short stalk called the petiolule.[1]: 87 There may be swollen regions at either end of the petiole known as pulvina (singular = pulvinus)[1]: 97 that are composed of a flexible tissue that allows leaf movement. Pulvina are common in the bean family Fabaceae and the prayer plant family Marantaceae. A pulvinus on a petiolule is called a pulvinulus.
In some plants, the petioles are flattened and widened to become phyllodes (also known as phyllodia or cladophylls) and the true leaves may be reduced or absent. Thus, the phyllode comes to serve the functions of the leaf. Phyllodes are common in the genus Acacia, especially the Australian species, at one time put in Acacia subgenus Phyllodineae.
In Acacia koa, the phyllodes are leathery and thick, allowing the tree to survive stressful environments. The petiole allows partially submerged hydrophytes to have leaves floating at different depths, the petiole being between the node and the stem.
In plants such as rhubarb (Rheum rhabarbarum), celery (Apium graveolens), artichokes, and cardoons (Cynara cardunculus), the petioles ("stalks" or "ribs") are cultivated as edible crops. The petiole of rhubarb grows directly from the rhizome and produces the leaf at its end. Botanically, it is categorized as a vegetable but, culinarily, it is more often used as a fruit.[6][7]
Etymology
Petiole comes from Latinpetiolus, or peciolus "little foot", "stem", an alternative diminutive of pes "foot". The regular diminutive pediculus is also used for "foot stalk".
petiole, botany, narrow, waist, some, hymenopteran, insects, petiole, insect, anatomy, botany, petiole, stalk, that, attaches, leaf, blade, stem, able, twist, leaf, face, this, gives, characteristic, foliage, arrangement, plant, outgrowths, appearing, each, si. For the narrow waist of some hymenopteran insects see Petiole insect anatomy In botany the petiole ˈ p iː t i oʊ l is the stalk that attaches the leaf blade to the stem 1 87 2 171 and is able to twist the leaf to face the sun This gives a characteristic foliage arrangement to the plant 3 Outgrowths appearing on each side of the petiole in some species are called stipules Leaves with a petiole are said to be petiolate while leaves lacking a petiole are called sessile or apetiolate citation needed Leaf of dog rose Rosa canina showing the petiole two leafy stipules the rachis and five leaflets Contents 1 Description 2 Etymology 3 See also 4 References 5 External linksDescription Edit Harvested rhubarb petioles with leaf blades attached Acacia koa with phyllode between the branch and the compound leaves Pulvina at both ends of the petiole Elaeocarpus multiflorus The petiole is a stalk that attaches a leaf to the plant stem In petiolate leaves the leaf stalk may be long as in the leaves of celery and rhubarb or short When completely absent the blade attaches directly to the stem and is said to be sessile Subpetiolate leaves have an extremely short petiole and may appear sessile 2 157 The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile 4 639 In some other plant groups such as the speedwell genus Veronica petiolate and sessile leaves may occur in different species 4 584 In the grasses Poaceae the leaves are apetiolate but the leaf blade may be narrowed at the junction with the leaf sheath to form a pseudopetiole as in Pseudosasa japonica 5 391 In plants with compound leaves the leaflets are attached to a continuation of the petiole called the rachis 1 98 Each leaflet may be attached to the rachis by a short stalk called the petiolule 1 87 There may be swollen regions at either end of the petiole known as pulvina singular pulvinus 1 97 that are composed of a flexible tissue that allows leaf movement Pulvina are common in the bean family Fabaceae and the prayer plant family Marantaceae A pulvinus on a petiolule is called a pulvinulus In some plants the petioles are flattened and widened to become phyllodes also known as phyllodia or cladophylls and the true leaves may be reduced or absent Thus the phyllode comes to serve the functions of the leaf Phyllodes are common in the genus Acacia especially the Australian species at one time put in Acacia subgenus Phyllodineae In Acacia koa the phyllodes are leathery and thick allowing the tree to survive stressful environments The petiole allows partially submerged hydrophytes to have leaves floating at different depths the petiole being between the node and the stem In plants such as rhubarb Rheum rhabarbarum celery Apium graveolens artichokes and cardoons Cynara cardunculus the petioles stalks or ribs are cultivated as edible crops The petiole of rhubarb grows directly from the rhizome and produces the leaf at its end Botanically it is categorized as a vegetable but culinarily it is more often used as a fruit 6 7 Etymology EditPetiole comes from Latin petiolus or peciolus little foot stem an alternative diminutive of pes foot The regular diminutive pediculus is also used for foot stalk See also EditHyponastic response PedicelReferences Edit a b c d Beentje H 2010 The Kew plant glossary London Kew Publishing ISBN 9781842464229 a b Mauseth James D 2003 Botany An Introduction to Plant Biology Jones amp Bartlett Learning ISBN 0 7637 2134 4 Archived copy Archived from the original on 2020 06 23 Retrieved 2020 06 22 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link a b Stace C A 2010 New Flora of the British Isles Third ed Cambridge U K Cambridge University Press ISBN 9780521707725 Heywood V H Brummitt R K Culham A Seberg O 2007 Flowering plant families of the world New York Firefly Books ISBN 9781554072064 Foust Clifford M 1992 Rhubarb The Wondrous Drug Princeton Princeton University Press ISBN 0 691 08747 4 High Altitude Rhubarb Highaltituderhubarb com Retrieved 9 June 2022 External links Edit Petiole Collier s New Encyclopedia 1921 Wikimedia Commons has media related to petioles Retrieved from https en wikipedia org w index php title Petiole botany amp oldid 1111086454, wikipedia, wiki, book, books, library,
