The upcoming discussion will update you about the differences between Primary Phloem and Secondary Phloem.
Difference # Primary Phloem:
1. It is formed from pro-cambium of apical meristem.
2. It is found in the primary plant body of all vascular plants.
3. Primary phloem occurs in all types of organs
4. It occurs towards the periphery.
5. Primary phloem is differentiated into proto- phloem and metaphloem.
6. A radial system is absent.
7. Phloem fibres are fewer. They are restricted to outer part.
8. Primary phloem shows an irregular arrangement of various types of cells.
9. Sieve tubes are comparatively fewer.
10. Sieve tubes are longer and narrower.
11. Phloem parenchyma is less abundant.
12. Crystals and other depositions are rare.
13. Sciereids are usually absent.
Difference # Secondary Phloem:
1. Secondary phloem develops from a lateral meristem called vascular cambium.
2. It is found only during secondary growth of dicots and gymnosperms with the exception of annuals.
3. Secondary phloem is restricted to stems and roots of perennial dicots and gymnosperms.
4. It is formed inner to the primary phloem.
5. There is no such distinction.
6. It is traversed by radial system of phloem rays.
7. Phloem fibres are more abundant. They commonly occur in patches or bands.
8. Secondary phloem has a more regular arrangement.
9. Sieve tubes are comparatively more numerous.
10. Sieve tubes are shorter but wider.
11. It is more abundant.
12. The cells often contain crystals and depositions of various substances.
13. Sciereids are formed in the secondary phloem of several plants.