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 determine how many cells are present in the embryo sac immediately after the pollen tube ruptures, we can follow these steps:

1. **Understand the Structure of the Embryo Sac**: The embryo sac consists of several types of cells. Initially, it contains:
- 3 antipodal cells
- 1 egg cell
- 2 synergid cells
- 2 polar nuclei (which are often considered as part of the central cell)

2. **Count the Initial Cells**: Before the pollen tube ruptures, we can count the cells:
- Antipodal cells: 3
- Egg cell: 1
- Synergid cells: 2
- Polar nuclei: 2 (considered as part of the central cell)

Adding these together gives us:
\[ 3 \text{ (antipodal)} + 1 \text{ (egg)} + 2 \text{ (synergids)} + 2 \text{ (polar nuclei)} = 8 \text{ cells} \]

3. **Pollen Tube Rupture**: When the pollen tube reaches the embryo sac, it releases two male gametes.

4. **Count the Additional Cells**: After the pollen tube ruptures:
- One male gamete fuses with one of the polar nuclei, forming a zygote.
- The second male gamete fuses with the other polar nucleus, forming the triploid endosperm.

This adds 2 more cells (the male gametes) to the total count.

5. **Calculate the Total Number of Cells**: Now, we can add the newly introduced male gametes to the initial count:
\[ 8 \text{ (initial cells)} + 2 \text{ (male gametes)} = 10 \text{ cells} \]

Thus, the total number of cells present in the embryo sac immediately after the pollen tube ruptures is **10 cells**.