Question

Explain the components of phloem tissue.

Answer 1

Phloem is a complex tissue and consists of the following elements:

1. Sieve elements
2. Companion cells
3. Phloem fibers
4. Phloem parenchyma

1. Sieve elements:

1. The conducting elements of phloem are collectively called Sieve elements.
2. Sieve tubes are elongated, tube-like slender cells placed end to end. The transverse walls at the ends are perforated and are known as sieve plates.
3. The main function of sieve tubes is the translocation of food, from leaves to the storage organs of the plants.

2. Companion cells: These are elongated cells attached to the lateral wall of the sieve tubes. A companion cell may be equal in length to the accompanying sieve tube element or the mother cell may be divided transversely forming a series of companion cells.

3. Phloem parenchyma: The phloem parenchyma is living cells that have cytoplasm and nucleus. Their function is to store food materials.

4. Phloem fibers: Sclerenchymatous cells associated with primary and secondary phloem are commonly called phloem fibers. These cells are elongated, lignified, and provide mechanical strength to the plant body.