A space occurs between nucellus and integument towards micropylar end. It is called

Options

A. Endostome
B. Endothecium
C. Endothelium
D. Endosperm.

Answer

To solve the question "A space occurs between nucellus and integument towards micropylar end. It is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of an Ovule**:
- The ovule consists of several parts, including the nucellus and integuments. The nucellus is the central part of the ovule, while the integuments are the protective layers surrounding it.

2. **Identify the Micropylar End**:
- The micropylar end is the end of the ovule where the pollen tube enters during fertilization. It is characterized by the absence of integuments at this point, forming a small opening.

3. **Define the Space Between Nucellus and Integument**:
- The question specifically asks about the space that occurs between the nucellus and the inner integument at the micropylar end. This space is crucial for the entry of the pollen tube.

4. **Identify the Correct Term**:
- The space between the nucellus and the inner integument towards the micropylar end is known as the **endostome**. This term is specifically used to describe this space.

5. **Evaluate the Options Provided**:
- Option A: Endostome - Correct answer.
- Option B: Endothelium - Incorrect, as it refers to a layer in pollen grains.
- Option C: Endothelium - Incorrect, as it is not relevant here.
- Option D: Endosperm - Incorrect, as it is formed as a result of triple fusion during fertilization.

6. **Conclusion**:
- Based on the definitions and the structure of the ovule, the correct answer to the question is **endostome**.

### Final Answer:
The space between the nucellus and integument towards the micropylar end is called **endostome**.

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