Question

The type of support tissues that consists of uneven thickened primary walls with elongated cells is called

• A. collenchyma's tissues
• B. phloem tissues
• C. xylem tissues
• D. parenchyma tissues

Hint:

Remember the unique cell wall characteristics:
- Parenchyma: Thin, uniform primary walls (flexible, metaboli(C).
- Collenchyma: Unevenly thickened primary walls (flexible support in growing parts).
- Sclerenchyma: Thick, lignified secondary walls (rigid support in mature parts).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks to identify a specific type of plant support tissue based on its cellular characteristics: elongated cells and unevenly thickened primary walls.

Step 3: Detailed Explanation:
Let's analyze the characteristics of each tissue type:
1. Collenchyma: This tissue consists of living cells that are typically elongated. Their primary cell walls are characteristically unevenly thickened, especially at the corners, due to the deposition of pectin and cellulose. Collenchyma provides flexible mechanical support to growing organs (like young stems, petioles of leaves) without hindering their growth.
2. Phloem: A complex tissue responsible for the transport of food. It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
3. Xylem: A complex tissue responsible for water and mineral transport. It consists of tracheids, vessels, xylem parenchyma, and xylem fibers. Its walls are typically lignified and uniformly thickened (secondary walls).
4. Parenchyma: This tissue consists of living cells with relatively thin, uniformly thickened primary cell walls. They are involved in various functions like storage, photosynthesis, and secretion.
The description "uneven thickened primary walls with elongated cells" perfectly matches collenchyma.

Step 4: Final Answer:
The correct option is (A) collenchyma's tissues.

Answer 2

The question describes a support tissue made of elongated cells with unevenly thickened primary cell walls, and each tissue option needs to be checked against that description.

1. Collenchyma tissue: Made of living, elongated cells whose primary walls thicken unevenly, usually more heavily at the corners, from extra deposits of pectin and cellulose. This uneven thickening lets young stems and leaf stalks bend without breaking while still getting mechanical support, which matches the description exactly.
2. Phloem tissue: This is a food-conducting tissue made of sieve tubes, companion cells, and phloem fibres. Its main job is transport, and it is not described in terms of unevenly thickened primary walls.
3. Xylem tissue: This is a water-conducting tissue whose cells (tracheids and vessels) develop hardened, lignified secondary walls that thicken fairly evenly or in set patterns, not the uneven primary-wall thickening the question describes.
4. Parenchyma tissue: Made of living cells with thin, evenly thickened primary walls, used mainly for storage and photosynthesis. The wall description here is even, not uneven, so it does not fit.

Only collenchyma is built from elongated cells with unevenly thickened primary walls used purely for mechanical support.

Therefore, the correct answer is Collenchyma tissue.