Vascular tissue

Vascular tissue

:"This is an article about vascular tissue in plants. For transport in animals, see Circulatory system."

Vascular tissue is a complex tissue found in vascular plants, meaning that it is composed of more than one cell type. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium. All the vascular tissues within a particular plant together constitute the vascular tissue system of that plant.

The cells in differentiated vascular tissue are typically long and slender. Since the xylem and phloem function in the conduction of water, minerals, and nutrients throughout the plant, it is not surprising that their form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the sections of a pipe might be. As the plant grows, new vascular tissue differentiates in the growing tips of the plant. The new tissue is aligned with existing vascular tissue, maintaining its connection throughout the plant.The vascular tissue in plants is arranged in long, discrete strands called vascular bundles. These bundles include both xylem and phloem, as well as supporting and protective cells. In stems and roots, the xylem typically lies closer to the interior of the stem with phloem towards the exterior of the stem. In the stems of some Asteriidae dicots, there may be phloem located inwardly from the xylem as well.

Between the xylem and phloem is a meristem called the vascular cambium. This tissue divides off cells that will be become additional xylem and phloem. This growth increases the girth of the plant, rather than its length. As long as the vascular cambium continues to produce new cells, the plant will continue to grow more stout. In trees and other plants that develop wood, the vascular cambium allows the expansion of vascular tissue that produces woody growth. Because this growth ruptures the epidermis of the stem, woody plants also have a cork cambium that develops among the phloem. The cork cambium gives rise to thickened cork cells to protect the surface of the plant and reduce water loss. Both the production of wood and the production of cork are forms of secondary growth.

In leaves, the vascular bundles are located among the spongy mesophyll. The xylem is oriented toward the adaxial surface of the leaf (usually the upper side), and phloem is oriented toward the abaxial surface of the leaf. This is why aphids are typically found on the underside of the leaves rather than on the top, since the phloem transports sugars manufactured by the plant and they are closer to the lower surface.

ee also

*Cork cambium
*Vascular cambium
*Vascular plant
*Stele (biology)

External links

* [ Intro to Plant Structure] Contains diagrams of the plant tissues, listed as an outline.

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Look at other dictionaries:

  • Vascular tissue — Vascular Vas cu*lar, a. [L. vasculum a small vessel, dim. of vas vessel: cf. F. vasculaire. See {Vase}, and cf. Vessel.] [1913 Webster] 1. (Biol.) (a) Consisting of, or containing, vessels as an essential part of a structure; full of vessels;… …   The Collaborative International Dictionary of English

  • vascular tissue — n. Bot. tissue composed of the xylem and phloem ducts that carry sap and food through any of the vascular plants …   English World dictionary

  • Vascular tissue neoplasm — Infobox Disease Name = PAGENAME Caption = DiseasesDB = ICD10 = ICD9 = ICDO = OMIM = MedlinePlus = eMedicineSubj = eMedicineTopic = MeshID = D009383 A vascular tissue neoplasm is, as its name would indicate, a vascular tissue tumor.cite web… …   Wikipedia

  • vascular tissue — noun tissue that conducts water and nutrients through the plant body in higher plants • Hypernyms: ↑plant tissue • Hyponyms: ↑stele, ↑cambium, ↑vascular bundle, ↑vascular strand, ↑fibrovascular bundle, ↑ …   Useful english dictionary

  • vascular tissue — noun a) The arteries, veins, capillaries, and associated tissues in an animal. b) The xylem, phloem, and associated tissues in a vascular plant. Syn: circulatory tissue See Also …   Wiktionary

  • vascular tissue — Bot. plant tissue consisting of ducts or vessels, that, in the higher plants, forms the system (vascular system) by which sap is conveyed through the plant. [1805 15] * * * …   Universalium

  • vascular tissue — noun Date: 1842 plant tissue concerned mainly with conduction; especially the specialized tissue of higher plants consisting essentially of phloem and xylem …   New Collegiate Dictionary

  • vascular tissue —   Supportive and conductive tissue in plants, consisting of xylem and phloem …   Expanded glossary of Cycad terms

  • vascular tissue — vas′cular tis sue n. bot plant tissue consisting of ducts or vessels that in the higher plants forms the system(vas′cular sys tem)by which sap is conveyed through the plant • Etymology: 1805–15 …   From formal English to slang

  • vascular tissue — /væskjələ ˈtɪʃu/ (say vaskyuhluh tishooh) noun plant tissue consisting of ducts or vessels which, in highly developed plants, form the system by which sap is conveyed through the plant …  

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