The matured embryo sac of Oenothera is

Options

A. 4 celled & 4 nucleated
B. 8 celled & 8 nucleated
C. 7 celled & 8 nucleated
D. 7 celled & 7 nucleated

Answer

To solve the question regarding the matured embryo sac of Oenothera, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Plant Type**:
- Oenothera is a flowering plant, classified as an angiosperm.

**Hint**: Remember that angiosperms are characterized by their flowering nature and seed production.

2. **Understand the Structure of the Embryo Sac**:
- The mature embryo sac of angiosperms, including Oenothera, is typically composed of 7 cells and 8 nuclei.

**Hint**: Focus on the cell and nucleus count as a defining feature of the embryo sac.

3. **Embryo Sac Formation**:
- The formation begins in the ovule, where a cell in the nucellus differentiates into a megaspore mother cell (diploid).
- This megaspore mother cell undergoes meiosis, resulting in four megaspores, of which three degenerate.

**Hint**: Remember the process of meiosis and how it leads to the formation of megaspores.

4. **Mitosis of the Surviving Megaspore**:
- The surviving megaspore undergoes three successive mitotic divisions.
- This results in the formation of a structure that eventually becomes the mature embryo sac.

**Hint**: Mitosis is key in increasing the number of nuclei in the embryo sac.

5. **Cell Arrangement in the Mature Embryo Sac**:
- The mature embryo sac consists of:
- 3 antipodal cells at the chalazal end,
- 2 synergids and 1 egg cell at the micropilar end,
- 1 central cell with 2 nuclei.

**Hint**: Visualize the arrangement of cells to understand their roles in fertilization.

6. **Conclusion**:
- Therefore, the mature embryo sac of Oenothera is characterized as having 7 cells and 8 nuclei.

**Hint**: Summarize the key features of the mature embryo sac to reinforce your understanding.

### Final Answer:
The matured embryo sac of Oenothera is 7-celled and 8-nucleated.