All Topics  
Tracheid

 

 
   Email Print
   Bookmark   Link
 

 

Tracheid
 
 
  Topics Tracheid Topic Home

Tracheids are elongated cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
s in the xylem
Xylem

In vascular plants, xylem is one of the two types of transport tissue, phloem being the other. The word "xylem" is derived from classical Greek language ????? , "wood", and indeed the best known xylem tissue is wood, though it is found throughout the plant....
 of vascular plant
Vascular plant

Vascular plants are those plants that have lignin tissue for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms....
s, serving in the transport of water and mineral salts. The build of tracheids will vary according to where they occur.

Tracheids are one of two types of tracheary elements, vessel element
Vessel element

A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers....
s being the other. All tracheary elements will develop a thick lignified cell wall, and at maturity the protoplast
Protoplast

File:Protoplasts Petunia sp.jpgProtoplast, from the ancient Greek p??t?? + verb p???? or p??tt? , initially referred to the first organized body of a species....
 has broken down and disappeared. The presence of tracheary elements is the defining characteristic of vascular plants to differentiate them from non-vascular plant
Non-vascular plant

Non-vascular plants is a general term for those plants without a vascular tissue . Although non-vascular plants lack these particular tissues, a number of non-vascular plants possess tissues specialized for internal transport of water....
s.

The two major functions that tracheids may fulfill are

In most cases, the prime function of tracheids is that of transporting water.






Discussion
Ask a question about 'Tracheid'
Start a new discussion about 'Tracheid'
Answer questions from other users
Full Discussion Forum



Encyclopedia


Tracheids are elongated cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
s in the xylem
Xylem

In vascular plants, xylem is one of the two types of transport tissue, phloem being the other. The word "xylem" is derived from classical Greek language ????? , "wood", and indeed the best known xylem tissue is wood, though it is found throughout the plant....
 of vascular plant
Vascular plant

Vascular plants are those plants that have lignin tissue for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms....
s, serving in the transport of water and mineral salts. The build of tracheids will vary according to where they occur.

Tracheids are one of two types of tracheary elements, vessel element
Vessel element

A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers....
s being the other. All tracheary elements will develop a thick lignified cell wall, and at maturity the protoplast
Protoplast

File:Protoplasts Petunia sp.jpgProtoplast, from the ancient Greek p??t?? + verb p???? or p??tt? , initially referred to the first organized body of a species....
 has broken down and disappeared. The presence of tracheary elements is the defining characteristic of vascular plants to differentiate them from non-vascular plant
Non-vascular plant

Non-vascular plants is a general term for those plants without a vascular tissue . Although non-vascular plants lack these particular tissues, a number of non-vascular plants possess tissues specialized for internal transport of water....
s.

The two major functions that tracheids may fulfill are
  • as part of the transport system
  • in structural support


In most cases, the prime function of tracheids is that of transporting water. They occur in vascular bundle
Vascular bundle

A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in vascular tissue, which exists in two forms: xylem and phloem....
s throughout the non-woody parts of the vascular plant and provide water and minerals collected by the roots to leaves and other parts of the plant (stem, flowers, fruits etc).

A good example of structural support is in softwood
Softwood

Softwood is timber obtained from coniferous trees . With the exception of bald cypress, tamarack, and larch, softwood trees are evergreens. Softwood is mostly obtained from the Baltic, Scandinavia, and North America and is the source of about 80% of the world's production of timber....
s where tracheids are the major cell type. Tracheids give softwood its strength.

Because tracheids have a much higher surface to volume ratio compared to vessel elements, they serve to hold water against gravity (by adhesion
Adhesion

Adhesion is the tendency of certain dissimilar molecules to cling together due to attractive forces....
) when transpiration
Transpiration

Transpiration is the evaporation of water from the aerial parts of plants, especially leaf but also Plant stems, flowers and roots. Leaf surfaces are dotted with openings called stoma that are bordered by guard cells....
 is not occurring. This is likely one mechanism that helps plants prevent air embolism
Air embolism

An air embolism, or more generally gas embolism, is a medical condition caused by gas bubbles in the bloodstream . Small amounts of air often get into the blood circulation accidentally during surgery and other medical procedures , but most of these air emboli enter the veins and are stopped at the lungs, and thus a venous air embolism...
s.

See also

  • Vessel element
    Vessel element

    A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers....
  • Xylem
    Xylem

    In vascular plants, xylem is one of the two types of transport tissue, phloem being the other. The word "xylem" is derived from classical Greek language ????? , "wood", and indeed the best known xylem tissue is wood, though it is found throughout the plant....


External links

  • Pictures of softwood tracheids and ; both in pine.