Xilema

Xilema is the botanical term for xylem, the vascular tissue of terrestrial plants that conducts water and dissolved minerals from the roots to the aerial organs and helps support the plant.

It consists of tracheary elements—tracheids in many gymnosperms and vessel elements in many angiosperms—together with supportive fibers and parenchyma. Primary xylem forms during primary growth from the procambium, while secondary xylem (wood) is produced by the vascular cambium and accounts for much of the plant's girth.

Water transport occurs primarily through hollow, lignified cells; movement is driven by cohesion-tension generated by transpiration, with minerals following the transpiration stream. The cell walls are rich in lignin, providing rigidity and structural support.

Xylem is present in all vascular plants. Angiosperms commonly possess vessel elements that form long vessels, while gymnosperms largely rely on tracheids. Species vary in xylem structure and density, influencing wood properties and ecological adaptations.

Significance: The xylem plays a central role in plant physiology and ecology. Its structure affects wood quality, growth rates, and drought tolerance. Xylem anatomy is also used in fields such as dendrochronology and climate research to infer past environmental conditions.