Question

Sieve cells can be traced in :

• A. Dicots
• B. Monocots
• C. Gymnosperms and pteridophytes
• D. Bryophytes

Answer 1

The correct option is C

Gymnosperms and pteridophytes

The correct option is C:

Explanation of the correct option :

Option C:

1. The conducting structure of the phloem is sieve tubes which are long, tube-like structures arranged longitudinally.
2. Sieve tubes are absent in pteridophytes and gymnosperms.
3. Sieve tubes are not organized in linear rows and thus are known as sieve cells.
4. In pteridophytes and gymnosperms, instead of sieve tubes sieve cells are present
5. Hence, sieve cells are not much specialized as sieve tubes of angiosperms and lack companion cells.
6. They help in the conduction of sucrose in lower plants like pteridophytes and gymnosperms.

Explanation of the incorrect option :

Option A:

1. Dicots are members of angiosperms.
2. Angiosperms have sieve tubes that are more specialized than sieve cells.
3. They help in translocation and have companion cells.

Option B:

1. Monocots are also members of angiosperms.
2. They also contain sieve tubes.

Option D:

Bryophytes are very primitive plants and they lack sieve cells.

Final answer: Sieve cells can be traced in gymnosperms and pteridophytes.