The minimum number of meiotic divisions required to produce 120 viable seeds in pea plant is …….. .

Options

A. 150
B. 60
C. 120
D. 90

Answer

To determine the minimum number of meiotic divisions required to produce 120 viable seeds in a pea plant, we can break down the problem into steps.

### Step-by-Step Solution:

1. **Understanding Gamete Production**:
- In pea plants, male gametes are produced from microspores through meiosis. Each microspore undergoes meiosis to produce 4 male gametes.
- Female gametes are produced from megaspores. Each megaspore undergoes meiosis to produce 1 female gamete.

2. **Calculating Male Gametes**:
- To produce 120 male gametes, we need to determine how many microspores are required. Since each microspore produces 4 male gametes:
\[ \text{Number of microspores needed} = \frac{120 \text{ male gametes}}{4 \text{ male gametes per microspore}} = 30 \text{ microspores} \]
- Each microspore undergoes 1 meiotic division to produce 4 male gametes. Therefore, the number of meiotic divisions required for male gametes is:
\[ \text{Meiotic divisions for male gametes} = 30 \text{ microspores} = 30 \text{ meiotic divisions} \]

3. **Calculating Female Gametes**:
- To produce 120 female gametes, we need to determine how many megaspores are required. Since each megaspore produces 1 female gamete:
\[ \text{Number of megaspores needed} = 120 \text{ female gametes} = 120 \text{ megaspores} \]
- Each megaspore undergoes 1 meiotic division to produce 1 female gamete. Therefore, the number of meiotic divisions required for female gametes is:
\[ \text{Meiotic divisions for female gametes} = 120 \text{ megaspores} = 120 \text{ meiotic divisions} \]

4. **Total Meiotic Divisions**:
- Now, we add the meiotic divisions required for both male and female gametes:
\[ \text{Total meiotic divisions} = \text{Meiotic divisions for male gametes} + \text{Meiotic divisions for female gametes} \]
\[ \text{Total meiotic divisions} = 30 + 120 = 150 \]

### Conclusion:
The minimum number of meiotic divisions required to produce 120 viable seeds in a pea plant is **150**.