Buds of trees act as sink in

Options

A. early spring
B. late spring
C. winter
D. autumn

Answer

### Step-by-Step Solution:

1. **Understanding the Concept of Source and Sink**:
- In plants, the terms "source" and "sink" refer to the parts of the plant involved in the transport of nutrients, particularly sugars. The source is typically where sugars are produced (like leaves), and the sink is where they are utilized or stored (like buds, roots, or fruits).

2. **Identifying the Role of Buds**:
- Buds are non-photosynthetic organs that require energy for growth and development. During certain seasons, they act as sinks, meaning they need to receive sugars for their growth.

3. **Considering Seasonal Changes**:
- The role of different plant parts as sources or sinks can change with the seasons. For example, during spring, buds are actively growing, while in other seasons, they may not require as much sugar.

4. **Analyzing the Seasons**:
- Early Spring: Buds are developing and need energy, thus acting as sinks.
- Late Spring: Buds may still be active, but they are transitioning as they mature.
- Winter: Buds are typically dormant and do not actively require sugars.
- Autumn: Plants are preparing for dormancy, and buds are not actively growing.

5. **Conclusion**:
- Based on the analysis, buds of trees act as sinks primarily in **early spring** when they require energy for growth and development.

### Final Answer:
Buds of trees act as sinks in **early spring**.

---