The main type of complex tissues are xylem and Phloem. Xylem is complex tissue and is also called Hydrome. This is responsible for the conduction of water in the plant. Cells of xylem are heterogenous in structure and function. Tracheids, vessels(tracheary elements), fibres and parenchyma are grouped together in xylem. Phloem is food conducting tissue. It is complex tissue, with sieve elements, companion cells, fibres and parenchyma.
Xylem vs PhloemXylem
1. Xylem is usually found deep in the plant
2. It conducts water or sap
3. In older plants, xylem often constitutes bulk of the plant body.
4. The conducting or tracheary cells are dead.
5. Xylem is made up of three types of dead cells (vessels, tracheids, xylem fibres)
6. There is one type of living cells (xylem parenchyma)
7. The conducting cells have lignin thickening in the wall.
8. Conducting elements are of two types: vessels and tracheids.
9. Tracheary elements have different types of wall thickenings.
10. Vessels are devoid of septa
11. Xylem provides mechanical strength.
1. Xylem is usually situated towards the outer side of the plant.
2. It conducts organic food
3. Phloem always forms a small part of the plant body.
4. The conducting cells are living.
5. Phloem contains only one type of dead cells (phloem fibres).
6. There are three types of living cells (sieve tube cells, companion cells and phloem parenchyma)
7. Wall of sieve tube does not possess lignin.
8. Conducting elements are of one type: sieve tube.
9. Wall thickenings are absent in the conducting channels.
10. Sieve tubes have bulging and porous septa
11. Phloem has no mechanical function.