The number of meiotic and mitotic divisions necessary for development of female gametophyte in angiosperms is…

Options

A. 1 meiosis and 2 mitosis
B. 1 mitosis and 3 meiosis
C. 1 meiosis and 1 mitosis
D. 1 meiosis and 3 mitosis.

Answer

To determine the number of meiotic and mitotic divisions necessary for the development of the female gametophyte in angiosperms, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Starting Point**: The development of the female gametophyte begins with the megaspor mother cell (megasporangium).

2. **Meiotic Division**: The megaspor mother cell undergoes meiosis. This process results in the formation of four haploid megaspores.
- **Key Point**: Out of these four megaspores, three will degenerate, leaving only one functional megaspore.

3. **Mitotic Divisions**: The functional megaspore then undergoes a series of mitotic divisions.
- The first mitotic division of the functional megaspore produces two nuclei.
- The second mitotic division results in four nuclei.
- The third mitotic division leads to eight nuclei.

4. **Formation of the Female Gametophyte**: After the eight nuclei are formed, the cell wall starts to develop around these nuclei, resulting in the formation of the mature female gametophyte, or embryo sac.
- The arrangement of these nuclei leads to the formation of various cell types:
- Two synergids and one egg cell at the micropylar end.
- Three antipodal cells at the chalazal end.
- Two polar nuclei in the center.

5. **Count the Divisions**:
- **Meiotic Divisions**: 1 (from the megaspor mother cell)
- **Mitotic Divisions**: 3 (to form the eight nuclei)

### Final Answer:
The total number of divisions necessary for the development of the female gametophyte in angiosperms is **1 meiosis and 3 mitosis**.