Vascular tissue is a complex conducting
tissue, formed of more than one cell type, found in
vascular plant
Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...
s. 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
The vascular cambium is the main growth tissue in the stems and roots of many plants, specifically in dicots such as buttercups and oak trees, gymnosperms such as pine trees, as well as in certain other vascular plants. It produces secondary xy ...
and the
cork cambium. All the vascular tissues within a particular plant together constitute the vascular tissue system of that plant.
The cells in 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
A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will includ ...
. These bundles include both xylem and phloem, as well as supporting and protective cells. In
stems and
root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...
s, the xylem typically lies closer to the interior of the stem with phloem towards the exterior of the stem. In the stems of some Asterales
dicot
The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...
s, 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 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
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s and other plants that develop
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
, the vascular cambium allows the expansion of vascular tissue that produces woody growth. Because this growth ruptures the
epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rel ...
of the stem,
woody plants also have a
cork cambium that develops among the phloem. The cork cambium gives rise to thickened
cork
Cork or CORK may refer to:
Materials
* Cork (material), an impermeable buoyant plant product
** Cork (plug), a cylindrical or conical object used to seal a container
***Wine cork
Places Ireland
* Cork (city)
** Metropolitan Cork, also known as G ...
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
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...
, the vascular bundles are located among the spongy
mesophyll
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...
. The xylem is oriented toward the
adaxial surface of the leaf (usually the upper side), and phloem is oriented toward the