Vascular Tissue
There are two types of vascular tissue: xylem and phloem
The xylem is principally a water transport tissue. It moves water and material dissolved in water from the roots to the leaves.
The xylem is composed of two tracheary elements.
Tracheary elements must die first before they assume their ultimate
function of transporting water and dissolved materials.
The xylem is composed of two tracheary elements: vessel elements and
tracheids.
Tracheids Tracheids have a tapered cylindrical structure. |
Vessel Elements Vessel elements are stacked together to form a conducting tissue.
They are the most evolved and look like hollow cylinders. |
The phloem consists primarily of living cells.
A characteristic cell of the phloem is the sieve tube member.
Sieve tube members often transport food.
Sieve Plates
Sieve plates appear when enzymes break up the ends of the tubes and connect the contents of neighboring cells.
The phloem often has companion cells with it. These cells aid in transport.