How many cells present in the embryo sac immediately after pollen tube ruptures within the embryo sac ?

Options

A. 10
B. 7
C. 8
D. 9

Answer

To solve the question of how many cells are present in the embryo sac immediately after the pollen tube ruptures within the embryo sac, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Embryo Sac**:
- The mature embryo sac (female gametophyte) typically contains **7 cells**. These cells include:
- 1 egg cell
- 2 synergids
- 3 antipodal cells
- 1 central cell containing 2 polar nuclei

2. **Consider the Role of the Pollen Tube**:
- When the pollen tube reaches the embryo sac, it releases **2 male gametes (sperm cells)** into the embryo sac.

3. **Calculate the Total Number of Cells**:
- Initially, there are **7 cells** in the embryo sac.
- After the pollen tube ruptures and releases the 2 sperm cells, the total number of cells becomes:
- 7 (existing cells) + 2 (sperm cells) = **9 cells**.

4. **Identify the Processes Involved**:
- One of the sperm cells fuses with the egg cell to form a zygote (this is called **syngamy**).
- The other sperm cell fuses with the central cell (which contains the 2 polar nuclei) to form the primary endosperm nucleus (this is called **triple fusion**).

5. **Conclusion**:
- Therefore, immediately after the pollen tube ruptures within the embryo sac, there are a total of **9 cells** present.

### Final Answer:
The number of cells present in the embryo sac immediately after the pollen tube ruptures is **9**.

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