In a guava fruit there were 300 seeds. How many meiotic divisions must have been involved in the development of this fruit ?

Options

A. 75
B. 300
C. 375
D. 450

Answer

To determine how many meiotic divisions are involved in the development of a guava fruit with 300 seeds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Seed Formation**: Each seed in a fruit is formed from the fertilization of an egg cell (ovule) by a pollen grain. Therefore, for 300 seeds, we need 300 pollen grains and 300 egg cells.

2. **Pollen Grain Formation**: Pollen grains are produced from microspore mother cells (microsporocytes) through meiosis. Each microspore mother cell undergoes meiosis to produce four pollen grains.

- To find the number of microspore mother cells needed for 300 pollen grains, we use the formula:
\[ \text{Number of microspore mother cells} = \frac{\text{Total pollen grains}}{4} \]
\[ \text{Number of microspore mother cells} = \frac{300}{4} = 75 \]

3. **Egg Cell Formation**: Egg cells are produced from megaspore mother cells (megasporocytes) through meiosis. Each megaspore mother cell undergoes meiosis to produce one egg cell.

- Therefore, for 300 egg cells, we need:
\[ \text{Number of megaspore mother cells} = \text{Total egg cells} = 300 \]

4. **Calculating Total Meiotic Divisions**:
- Each microspore mother cell undergoes one meiotic division to produce four pollen grains. Thus, 75 microspore mother cells will undergo 75 meiotic divisions.
- Each megaspore mother cell undergoes one meiotic division to produce one egg cell. Thus, 300 megaspore mother cells will undergo 300 meiotic divisions.

5. **Total Meiotic Divisions**:
\[ \text{Total meiotic divisions} = \text{Meiotic divisions from microspore mother cells} + \text{Meiotic divisions from megaspore mother cells} \]
\[ \text{Total meiotic divisions} = 75 + 300 = 375 \]

### Final Answer:
The total number of meiotic divisions involved in the development of the guava fruit with 300 seeds is **375**.

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