Question

Which one of the following mature cell types is live but usually lacks nucleus?

• A. Phloem parenchyma
• B. Phloem companion
• C. Phloem sieve element
• D. Phloem-pole pericycle

Hint:

Sieve elements are the only living plant cells without a nucleus, relying on companion cells for survival and function.

Answer 1

The Correct Option is C

Phloem consists of several types of cells including sieve elements, companion cells, phloem parenchyma, and fibers.
Among these, phloem sieve elements are unique because they are living at maturity but lack a nucleus.
This structural adaptation allows for more efficient translocation of sugars and other organic substances throughout the plant.
However, the loss of the nucleus also makes them dependent on adjacent companion cells, which provide metabolic support.
Other phloem cells like phloem parenchyma and companion cells retain their nuclei and perform different functions.