Duramen is used as timber because

Options

A. it has large amount of vascular tissue
B. it has nutritive substances
C. it has secondary thickening
D. chemicals in tyloses provided durability.

Answer

**Step-by-Step Solution:**

1. **Understanding Duramen and Alburnum**:
- Duramen, also known as heartwood, is the central part of a tree trunk that is typically darker and denser than the outer layers. Alburnum, or sapwood, is the outer layer that is still functional in transporting water and nutrients.

2. **Structure of Duramen**:
- In duramen, the cells have undergone a process where their lumen (the hollow part of the cell) gradually disappears. This occurs as the tree matures, and the cells become non-functional and dead.

3. **Role of Tyloses**:
- Tyloses are outgrowths that occur in the vessels of the xylem (the tissue responsible for water transport). They can block the vessels and are formed in the cells of duramen. These tyloses contain chemicals that contribute to the durability of the wood.

4. **Comparison with Alburnum**:
- Unlike duramen, alburnum has a broader lumen and is still functional, meaning it has living cells that can transport nutrients and water. Alburnum does not have tyloses, which means it lacks the same level of durability as duramen.

5. **Conclusion**:
- Therefore, the reason duramen is used as timber is primarily due to the presence of tyloses, which provide durability to the wood. This makes duramen more suitable for construction and furniture-making compared to alburnum.

**Final Answer**: Duramen is used as timber because the chemicals in tyloses provide durability.

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