Sometimes more than 4 pollen grains are produced from one microspore mother cell, it is called

Options

A. Polyembryony
B. Polysiphony
C. Nemec phenomenon
D. Polyspory

Answer

### Step-by-Step Solution:

1. **Understanding the Microspore Mother Cell**: A microspore mother cell (also known as a microsporocyte) is a diploid cell that undergoes meiosis to produce haploid microspores. Each microspore can develop into a pollen grain.

2. **Normal Pollen Grain Production**: Typically, one microspore mother cell produces four pollen grains through the process of meiosis. This is the standard outcome in most flowering plants.

3. **Identifying the Condition of More Than Four Pollen Grains**: The question states that sometimes more than four pollen grains are produced from one microspore mother cell. This is an abnormal condition and requires a specific term.

4. **Exploring the Options**:
- **Polyembryony**: This term refers to the formation of multiple embryos from a single fertilized egg. This is not relevant to pollen grain production.
- **Polysiphony**: This term describes a condition where multiple pollen tubes invade the embryo sac, which is also not related to the production of pollen grains from a microspore mother cell.
- **Polyspory**: This term specifically refers to the condition where more than four pollen grains are produced from one microspore mother cell. This is the correct term for the situation described in the question.

5. **Conclusion**: Therefore, the correct answer to the question is **Polyspory**.