Cambium
/ˈkæmbiəm/
Definition
Cambium is a thin layer of actively dividing cells in vascular plants, found between xylem and phloem in stems, roots, and many woody parts. It is a meristem, meaning tissue that produces new cells. The vascular cambium makes secondary xylem to the inside and secondary phloem to the outside, increasing stem and root thickness. A cork cambium may also form near the surface, producing protective outer tissues.
Function in Plants
- Secondary thickening: It drives secondary growth, which increases stem and root girth rather than length. This is why many trees and shrubs become thicker year after year.
- Wood and inner bark production: Its activity produces secondary xylem to the inside and secondary phloem to the outside. Those tissues become the wood and part of the inner bark that move water, sugars, and dissolved nutrients.
- Healing and grafting: When stems are wounded, active cells near cambium help form repair tissue. In grafting, close contact between matching layers is important because new vascular connections must develop across the union.
- Common in woody plants: It is most evident in woody dicots and gymnosperms, including many landscape trees. Most monocots, such as grasses and palms, do not have the same pattern of thickening, so their trunks and stems develop differently.
Related Terms
Xylem
Xylem is the plant vascular tissue that carries water and dissolved minerals from the roots to stems and leaves. It…
Phloem
Phloem is the plant vascular tissue that transports sugars and other organic nutrients made during photosynthesis from…
Vascular tissue
Vascular tissue is the plant transport system, made of xylem and phloem. Xylem carries water and dissolved minerals…
Bark
Bark is the protective outer covering of woody stems, trunks, and roots in trees and shrubs. In botanical use, it…
Stem
Stem refers to the main aboveground plant structure that supports leaves, buds, flowers, and fruits, and connects them…
Root
Root refers to the plant organ, usually below ground, that anchors the plant and absorbs water and dissolved minerals…
Meristem
Meristem is plant tissue made of undifferentiated cells that keep dividing to produce new cells. It is the source of…
Tree
Tree refers to a long-lived woody plant form, usually with one main trunk and a raised crown of branches and leaves…