Question

Sieve tubes and companion cells are present in ___________ .

• A. xylem
• B. phloem
• C. cambium
• D. cork

Answer 1

The correct option is option (B):

Explanation for the correct option:

1. Phloem is a complex tissue which is concerned with the transport of food materials from leaves to other plant parts.
2. Phloem is composed of sieve tube elements, companion cells, phloem parenchyma and phloem fibres.
3. sieve tubes are longitudinally arranged cells.
4. It is seen associated with the companion cells.
5. Sieve tubes contain large cytoplasm without nucleus and its activity is controlled by sieve tubes.

Explanation for incorrect options:

Option (A):

1. Cambium is a thin formative layer between the xylem and phloem of most vascular plants that gives rise to new cells.
2. It is responsible for secondary growth, i.e., increase in girth of the plant.

Option (C):

1. The outer protective coat of a tree is called cork.
2. It is one of the components of tree bark.
3. The tissues of bark become old and the secondary meristem replaces them.

Option (D):

1. Xylem is a complex tissue which is concerned with the transport of water from roots to other plant parts.
2. It is composed of tracheids, vessels, xylem fibres and xylem parenchyma.

Final answer: Sieve tubes are found in the Phloem.