Pit membrane of simple pit is formed by :-

Options

A. Secondary cell wall
B. Middle lamella
C. Primary cell wall
D. Plasma membrane

Answer

To answer the question "Pit membrane of simple pit is formed by:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of a Simple Pit**:
- A simple pit is a type of pit found in plant cells, particularly in xylem and phloem tissues. It consists of a pit cavity and a pit membrane.

2. **Identify the Options Given**:
- The options provided are:
1. Secondary cell wall
2. Middle lamella
3. Primary cell wall
4. Plasma membrane

3. **Evaluate Each Option**:
- **Option 1: Secondary Cell Wall**:
- This option is incorrect because the pit cavity is formed due to the absence of the secondary cell wall. The secondary cell wall is not involved in forming the pit membrane.

- **Option 2: Middle Lamella**:
- This option is correct. The pit membrane is primarily formed from the degraded middle lamella of the two opposing cells. The middle lamella is the layer that cements adjacent plant cells together, and when it degrades, it contributes to the formation of the pit membrane.

- **Option 3: Primary Cell Wall**:
- This option is incorrect. The primary cell wall is the outermost layer of a plant cell and does not specifically form the pit membrane.

- **Option 4: Plasma Membrane**:
- This option is also incorrect. The plasma membrane surrounds the entire cell and does not contribute to the formation of the pit membrane.

4. **Conclusion**:
- Based on the evaluation of the options, the correct answer is **Middle Lamella** (Option 2).

### Final Answer:
The pit membrane of a simple pit is formed by the **middle lamella**.

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