ln grass what happens in microspore mother cell for the formation of mature pollen grain

Options

A. One meiotic and two mitotic divisions
B. One meiotic & one mitotic divisions
C. One meiotic division
D. One mitotic division

Answer

To understand the process that occurs in the microspore mother cell (MMC) for the formation of mature pollen grains in grass, let's break it down step by step:

### Step-by-Step Solution:

1. **Identify the Microspore Mother Cell (MMC)**:
- The microspore mother cell, also known as the pollen mother cell (PMC), is a diploid cell found in the sporogenous tissue of the anther in flowering plants, including grasses.

2. **Meiotic Division**:
- The MMC undergoes meiosis, which is a type of cell division that reduces the chromosome number by half. This process consists of two successive divisions: meiosis I and meiosis II.
- After meiosis I, the MMC divides to form two haploid cells, and after meiosis II, these cells further divide to produce a total of four haploid microspores.

3. **Formation of Microspores**:
- The four haploid microspores are formed as a result of the meiotic division of the MMC. This process is referred to as microsporogenesis.

4. **Mitotic Division**:
- After the formation of the four microspores, each microspore undergoes a mitotic division. This mitotic division is necessary for the development of the mature pollen grain.
- The mitotic division results in the formation of a pollen grain that typically consists of two cells: the generative cell and the vegetative cell.

5. **Final Structure of Mature Pollen Grain**:
- The mature pollen grain is thus formed after one meiotic division (producing four microspores) followed by one mitotic division (resulting in the two-cell structure).

### Conclusion:
In summary, in grasses, the microspore mother cell undergoes one meiotic division followed by one mitotic division to form mature pollen grains. Therefore, the correct answer is **Option 2: One meiotic and one mitotic division**.