Abscission zone is characterized by
(a) Presence of callose plugs
(b) Presence of a distinct layer
(c) Activity of celluloses and pectinases
(d) All of these

Options

A. Presence of callose plugs
B. Presence of a distinct layer
C. Activity of celluloses and pectinases
D. All of these

Answer

To solve the question about the characteristics of the abscission zone, let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding Abscission Zone**: The abscission zone is a specialized area in plants where leaves, fruits, or flowers detach from the plant. This zone is crucial for the process of abscission.

2. **Identifying Layers in the Abscission Zone**: The abscission zone typically consists of two main layers:
- **Separating Layer**: This layer is responsible for the actual separation of the leaf from the plant.
- **Protective Layer**: This layer helps protect the plant from pathogens and environmental factors after the leaf has been detached.

3. **Role of Callose**: When the leaf is about to be excised, callose (a carbohydrate) is deposited in the abscission zone. This forms callose plugs that help seal off the area where the leaf was attached, preventing water loss and protecting against infection.

4. **Activity of Enzymes**: In the abscission zone, enzymes such as celluloses and pectinases are active. These enzymes break down cell walls, facilitating the separation of the leaf from the plant.

5. **Conclusion**: Given the characteristics of the abscission zone, we can conclude that it is characterized by:
- Presence of callose plugs (true)
- Presence of a distinct layer (true)
- Activity of celluloses and pectinases (true)

6. **Final Answer**: Since all the statements are true, the correct answer is (d) All of these.