Which of the following xylem elements lack lignified cell wall ?

Options

A. Vessels
B. Xylem parenchyma
C. Xylem fibres
D. Both (A) and (B)

Answer

To solve the question "Which of the following xylem elements lack lignified cell wall?", we will analyze each of the xylem components provided in the options.

### Step-by-Step Solution:

1. **Understand Xylem Structure**:
- Xylem is a type of vascular tissue in plants responsible for the transport of water and minerals from the roots to other parts of the plant.

2. **Identify Xylem Components**:
- The main components of xylem include xylem vessels, xylem parenchyma, and xylem fibers.

3. **Evaluate Each Option**:
- **Option A: Xylem Vessels**:
- Xylem vessels are composed of lignified cell walls that provide structural support and facilitate the conduction of water. Therefore, this option is incorrect.

- **Option B: Xylem Parenchyma**:
- Xylem parenchyma cells are living cells that do not have lignified walls. They primarily serve in storage and can also assist in the transport of water. This option is correct as they lack lignified cell walls.

- **Option C: Xylem Fibers**:
- Xylem fibers have lignified walls that provide mechanical strength to the plant. Hence, this option is also incorrect.

- **Option D: Both A and B**:
- Since option A (xylem vessels) is incorrect and option B (xylem parenchyma) is correct, this option is incorrect as well.

4. **Conclusion**:
- The only xylem element that lacks a lignified cell wall is **xylem parenchyma**. Therefore, the correct answer is **Option B**.

### Final Answer:
**Xylem Parenchyma (Option B)**