Difference between Primary and Secondary xylem
No. |
Primary xylem |
Secondary xylem |
1. | During the primary growth with the help of Procambium, formation of xylem occurs and it is known as primary xylem. | During the secondary growth of vascular cambium, formation of xylem takes place and it is known as secondary xylem. |
2. | Primary xylem is a primary type of growth. | Secondary xylem is a secondary type of growth. |
3. | Vessel of primary xylem are long and thin. | Vessel of secondary xylem are short and wide. |
4. | In the primary xylem, tracheids do not have pits. | In the secondary xylem, tracheids have thickenings and forms pits. |
5. | Primary xylem have fewer xylem fibers. | Secondary xylem have large amount of xylem fibers. |
6. | All the types of gymnosperms contain primary xylem. | Some of gymnosperms like Gnetophyta, conifers, Gingkophyta and Cycadophyta. |
7. | Primary xylem is divided into the protoxylem and metaxylem. | Secondary xylem is takes part inside the bark. |
8. | Tyloses in primary xylem are absent. | Tyloses in secondary xylem are present. |