Which one of the following alternatives represents the gametophytic phase in Pinus

Options

A. Male and female cones
B. Micro- and mega- spores
C. Zygote
D. Pinus plant.

Answer

To determine which alternative represents the gametophytic phase in Pinus, we need to understand the life cycle of gymnosperms, particularly focusing on the phases involved.

### Step-by-Step Solution:

1. **Understand the Life Cycle of Pinus**:
- Pinus, like other gymnosperms, has two main phases in its life cycle: the sporophytic phase and the gametophytic phase. The sporophyte is the dominant phase, while the gametophyte is reduced.

2. **Identify the Gametophytic Phase**:
- The gametophytic phase is characterized by the production of gametes. In gymnosperms, the male gametophyte is represented by pollen grains, which develop from microspores. The female gametophyte is represented by the megaspore, which develops into the ovule.

3. **Analyze the Options**:
- **Option A: Male and female cones** - These are structures of the sporophyte phase, not the gametophyte.
- **Option B: Micro and megaspores** - Microspores develop into male gametophytes (pollen grains), and megaspores develop into female gametophytes. This option correctly represents the gametophytic phase.
- **Option C: Zygote** - This is a result of fertilization and represents the sporophytic phase.
- **Option D: Pinus plant** - This refers to the entire plant, which is the sporophyte.

4. **Conclusion**:
- The correct answer is **Option B: Micro and megaspores**, as they represent the gametophytic phase in Pinus.