Question

Which of the following is correct regarding plant tissues?

• A. The collenchyma occurs in layers below the epidermis in monocotyledonous plants.
• B. The xylem parenchyma cells are living and thin-walled, and their cell walls are made up of lignin.
• C. Sclerenchyma cells are usually dead and without protoplasts.
• D. The companion cells are specialised sclerenchymatous cells.

Answer 1

The correct option is C

Sclerenchyma cells are usually dead and without protoplasts.

The correct option is C.

Explanation of the correct option:

1. Sclerenchyma cells have lignified cell walls which give mechanical support to plants.
2. Mature sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin.
3. Sclerenchyma cells are usually dead and without protoplasts. The collenchyma occurs in layers below the epidermis in dicotyledonous plants.
4. Xylem parenchyma cells have thin cell walls made of cellulose. Companion cells are parenchymatous cells.

Explanation of the incorrect option:

Option A:

Collenchyma tissue is composed by elongated living cells of uneven primary thick walls, which possess hemicellulose, cellulose, and pectic materials.

Option B:

Xylem parenchyma cells can store water, which is essential for the proper functioning of a plant.

Option D:

Companion cells are specialised parenchymatous cells that are closely associated with the sieve tube elements in the phloem

Final answer: Correct regarding plant tissues sclerenchyma cells are usually dead and without protoplasts.