Xylem Tissue
Xylem transports water up the plant. Xylem is a complex tissues in that it always has more than one cell type. Xylem always includes tracheary elements. These are dead at maturity, and always have secondary walls. These also have pits. If a tracheary element only has pits, then it is considered a tracheid. If a tracheary element also has perforations, then it is considered to be a vessel element. Conifers only have tracheids. Flowering plants can have both.
- Link to image of a cross section of Medicago stem showing the detail of a vascular bundle. Xylem is towards the inside, and phloem is towards the outside.
- Link to image of a cross section of Medicago stem showing the detail of the xylem facing the pith. The red-stained cells are vessel elements.
- Link to image of a cross section of Cucurbita stem showing xylem tissue consisting of vessel elements and parenchyma cells
- Link to image of a longitudinal section of Cucurbita stem showing a vessel with pitted secondary walls.
- Link to image of a longitudinal section of Cucurbita stem showing vessel elements with incomplete secondary walls.
- Link to image of a longitudinal section of Cucurbita stem showing pits.
- Link to image of a cross section of Pinus stem showing xylem consisting of tracheid with pits
- Link to image of a cross section of Pinus stem showing xylem with tracheids and parenchyma cells.
- Link to view of a vessel element of macerated oak wood.
- Link to view of tracheid of macerated pine wood.
- Pine tracheids showing pits.
- Xylem of a carrot root. Tissue consists of vessel element and lots of parenchyma cells.
