Lignin occurs in the cell walls of

Options

A. phloem
B. cork Cambium
C. woody tissue
D. parenchyma

Answer

**Step-by-Step Solution:**

1. **Understanding Lignin**: Lignin is a complex organic polymer found in the cell walls of many plants. It provides rigidity and strength to the cell walls, especially in woody plants.

2. **Types of Cell Walls**: Lignin is present in two types of cell walls: the primary cell wall and the secondary cell wall. The primary cell wall is formed first when a cell divides, while the secondary cell wall is formed later as the cell matures.

3. **Formation of Secondary Cell Wall**: The secondary cell wall is formed between the primary cell wall and the plasma membrane once the cell has completed its growth. This indicates that the cell is mature and will not grow further.

4. **Composition of Secondary Cell Wall**: The secondary cell wall is composed of cellulose microfibrils and lignin. The presence of lignin in the secondary cell wall is significant for the structural integrity of the plant.

5. **Location of Lignin**: Lignin is predominantly found in the cell walls of mature xylem cells. These cells are responsible for water transport in plants and are heavily lignified, contributing to the hardness of wood.

6. **Conclusion**: Therefore, lignin occurs in the cell walls of woody tissue and specifically in xylem cells. If the options provided include "woody tissue" or "xylem cells," either could be correct depending on the context of the question.

**Final Answer**: Lignin occurs in the cell walls of woody tissue and xylem cells.

---