Autumn wood is distinguishable from spring wood in having

Options

A. narrow tracheary elements
B. broader tracheary elements
C. lighter colour
D. cambium

Answer

To determine how autumn wood is distinguishable from spring wood, we need to analyze the characteristics of both types of wood.

### Step-by-Step Solution:

1. **Understanding Wood Formation**:
- Wood is formed from the secondary xylem produced by the vascular cambium. The formation of wood varies with the seasons.

2. **Identifying Spring Wood**:
- Spring wood, also known as early wood, is formed during favorable conditions (spring season).
- During this time, the vascular cambium is highly active, leading to the production of large, broad tracheary elements (the cells that conduct water).

3. **Identifying Autumn Wood**:
- Autumn wood, also known as late wood, is formed during unfavorable conditions (autumn or winter).
- The activity of the vascular cambium decreases, resulting in the formation of narrower and thicker tracheary elements compared to spring wood.

4. **Comparing Tracheary Elements**:
- In autumn wood, the tracheary elements are narrower and more thickened due to reduced growth and water transport needs.
- In contrast, spring wood has broader tracheary elements that facilitate increased water transport during the growing season.

5. **Evaluating the Options**:
- **Narrow trachea elements**: This is true for autumn wood.
- **Broader trachea elements**: This is true for spring wood, so this option is incorrect for autumn wood.
- **Lighter color**: Spring wood is typically lighter in color, while autumn wood is darker, making this option incorrect.
- **Cambium**: Both types of wood have cambium, so this option does not distinguish between them.

6. **Conclusion**:
- The distinguishing feature of autumn wood compared to spring wood is the presence of narrow trachea elements.

### Final Answer:
Autumn wood is distinguishable from spring wood in having **narrow trachea elements**.

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