Vascular cambium
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The vascular cambium (pl. cambia or cambiums) is a part of the morphology of plants. It consists of cells that are partly specialized, for the tissues that transport water solutions, but have not reached any of the final forms that occur in their branch of the specialization graph. When these cells have divided and specialized further they make up the secondary vascular tissues, secondary xylem and the secondary phloem.
The vascular cambium is a lateral meristem in the vascular tissue of plants. The vascular cambium is the source of both the secondary xylem (inwards, towards the pith) and the secondary phloem (outwards), and is located between these tissues in the stem and root. A few leaf types also have a vascular cambium.[2]
[edit] Origin
Vascular cambium arises from the primary meristem, procambium that remains undifferentiated between the primary xylem and primary phloem. Upon maturity, this region known as the fascicular cambium, and the area of cells between the vascular bundles (fascicles) called pith rays becomes what is called the interfascicular cambium. The fascicular and interfascicular cambiums, therefore, represent a continuous ring which bisects the primary xylem and primary phloem. The vascular cambium then produces secondary xylem on the inside of the ring, and secondary phloem on the outside, pushing the primary xylem and phloem apart.
The vascular cambium usually consists of two types of cells:
- Fusiform initials (tall cells, axially oriented)
- Ray initials (almost isodiametric cells - smaller and round to angular in shape)
The vascular cambium is a type of meristem - tissue consisting of embryonic (incompletely differentiated) cells from which other (more differentiated) plant tissues originate. Primary meristems are the apical meristems on root tips and shoot tips. Another lateral meristem is the cork cambium, which produces cork, part of the bark. Together, the secondary vascular tissues (produced by the vascular cambium) and periderm (formed by the cork cambium) makes up the secondary plant body.
Vascular cambia are found in dicots and gymnosperms but not monocots, which usually lack secondary growth.
For successful grafting, the vascular cambia of the stock and scion must be aligned so they can grow together.
[edit] Synonyms
- Wood cambium
- Main cambium
- Bifacial cambium
[edit] See also
[edit] References
[edit] External links
- Pictures of Vascular cambium
- Detailed description - James D. Mauseth
- Review: Risopatron JPM, Sun YQ, Jones BJ (2010) The vascular cambium: Molecular control of cellular structure. Protoplasma 247 (3-4):145-161. doi:10.1007/s00709-010-0211-z (http://www.ncbi.nlm.nih.gov/pubmed/20978810)
