Which macroelement is required in the middle lamellae of the cell wall?

Options

A. potassium
B. calcium
C. phosphorus
D. nitrogen

Answer

**Step-by-Step Solution:**

1. **Understanding the Cell Wall Structure:**
- Plant cells have a cell wall made primarily of cellulose. This wall provides structural support and protection to the cell.

2. **Identifying the Middle Lamella:**
- The middle lamella is a layer that exists between the cell walls of adjacent plant cells. It acts as a glue that cements these walls together.

3. **Composition of the Middle Lamella:**
- The middle lamella is rich in pectins, which are polysaccharides that help in binding cells together.

4. **Role of Macroelements:**
- Macroelements are essential nutrients required in larger quantities for plant growth and development. They include elements like Calcium, Potassium, Phosphorus, and Nitrogen.

5. **Key Macroelement in the Middle Lamella:**
- Among the options provided (Potassium, Calcium, Phosphorus, Nitrogen), Calcium is specifically mentioned as a significant component of pectin in the middle lamella.

6. **Conclusion:**
- Therefore, the macroelement required in the middle lamellae of the cell wall is **Calcium**.

**Final Answer: Calcium**

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