What is the Difference Between Primary Xylem and Secondary Xylem?
🆚 Go to Comparative Table 🆚The main difference between primary xylem and secondary xylem lies in their origin and development. Here are the key differences between the two:
- Origin: Primary xylem is formed by the primary growth of the procambium, while secondary xylem is formed by the secondary growth of the vascular cambium.
- Plant Parts: Primary xylem is found in all vascular plants' primary plant bodies, while secondary xylem is restricted to the stems and roots of perennial dicots and gymnosperms.
- Position: Primary xylem occurs in the center, while secondary xylem occurs towards the outer side of the primary xylem.
- Structure: Primary xylem is composed of protoxylem and metaxylem, while secondary xylem does not have such a distinction.
- Tracheids and Vessels: Primary xylem contains long and thin tracheids and vessels, while secondary xylem contains shorter and wider tracheids and vessels.
- Fibers: Primary xylem has few or no fibers, while secondary xylem usually contains abundant fibers.
- Radial System: Primary xylem lacks a radial system, while secondary xylem is traversed by a radial system of xylem rays.
- Annual Rings: Primary xylem does not have annual rings, while secondary xylem may show annual rings.
- Sapwood and Heartwood: In primary xylem, there is no distinction between sapwood and heartwood, while in secondary xylem, a distinction is present in large woody plants.
In summary, primary xylem is formed during the primary growth of a plant and is found in all vascular plant parts, while secondary xylem is formed during secondary growth and is restricted to the stems and roots of certain plants. The structure, composition, and properties of the two types of xylem are distinct, serving different functions in plant growth and development.
Comparative Table: Primary Xylem vs Secondary Xylem
Primary xylem and secondary xylem are two types of xylem tissues that play a crucial role in plant growth and water transport. Here is a table highlighting the differences between primary xylem and secondary xylem:
| Feature | Primary Xylem | Secondary Xylem |
|---|---|---|
| Origin | Formed from the procambium of the apical meristem | Formed from the vascular cambium, a lateral meristem |
| Growth | Occurs during primary growth | Occurs during secondary growth |
| Position | Found in all vascular plants' primary plant bodies | Affects the stems and roots of perennial dicots and gymnosperms |
| Arrangement | Center of the plant | Outer side of the primary xylem |
| Structure | Patches of primary xylem can be identified | Forms a cylinder |
| Components | Protoxylem and metaxylem | No distinction between protoxylem and metaxylem |
| Radial System | No radial system | Traversed by a radial system of xylem rays |
| Annual Rings | No annual rings | Annual rings are present |
| Sapwood and Heartwood | No distinction | Distinguishable in large woody trees |
| Fibers | Few or absent | Generally abundant |
| Tracheid and Vessel Structure | Long and thin-walled | Shorter and thicker than the rest of the body |
| Thickenings in Tracheary Components | Various types of thickenings can occur | Pitted thickenings are prevalent |
| Tyloses | Usually absent | Tyloses grow and obstruct the arteries and tracheid of older xylem cells |
In summary, primary xylem is derived from the procambium of the apical meristem during primary growth, while secondary xylem is derived from the vascular cambium during secondary growth. Primary xylem is found in all vascular plants and plays a crucial role in water transport, whereas secondary xylem is restricted to stems and roots of perennial dicots and gymnosperms and provides additional mechanical support.
- Xylem vs Phloem
- Protoxylem vs Metaxylem
- Primary vs Secondary Growth
- Primary vs Secondary Mycelium
- Primary vs Secondary Dentin
- Tracheids vs Vessels
- Vascular Cambium vs Cork Cambium
- Primary vs Secondary Minerals
- Primary Succession vs Secondary Succession
- Primary vs Secondary Cells
- Heartwood vs Sapwood
- Primary vs Secondary Peristalsis
- Primary vs Secondary Active Transport
- Primary vs Secondary Hemostasis
- Primary vs Secondary Cell Culture
- Collenchyma vs Sclerenchyma
- Vascular vs Nonvascular Plants
- Parenchyma vs Sclerenchyma
- Lignin vs Cellulose