Xylem tissue consists of the following cells EXCEPT

Step 1: Analyze the question We are asked which cell type is NOT found in xylem tissue.

Step 2: Concept Xylem is the plant tissue that conducts water and mineral salts from the roots upward. It also gives mechanical support. It is made up of:

• Tracheids: elongated, dead cells with lignified walls that carry water and give support.
• Vessels (tracheae): long tubes formed from dead cells joined end to end, with the end walls broken down.
• Xylem fibres: sclerenchyma cells that give mechanical strength.
• Xylem parenchyma: living cells that store food and help in lateral transport.

Phloem is the tissue that conducts manufactured food (sugars). It is made up of:

• Sieve tubes
• Companion cells
• Phloem parenchyma and phloem fibres

Step 3: Solution

• A. Sieve tubes: part of the phloem, not the xylem.
• B. Tracheids: found in xylem.
• C. Vessels: found in xylem.
• D. Fibres: found in xylem.
• E. Parenchyma: found in xylem.

Only sieve tubes do not belong to xylem, so they are the exception.

Answer: A. Sieve tubes

Tip: Remember that sieve tubes and companion cells belong to the phloem. Xylem = "Tough Vessels Fibres Parenchyma", meaning tracheids, vessels, fibres and parenchyma. Also, xylem carries water up, while phloem carries food both ways. Sieve plates (like a sieve) help you link sieve tubes to phloem.