In some fungi such as……………, the fusion of two haploid cells immediately results in diploid cell while in other group of fungi like …………., an intervening dikaryotic stage occurs, called dikaryophase.
Phycomycetes , Basidiomycetes
Basidiomycetes, Ascomycetes
Ascomycetes, Phycomycetes
Phycomycetes , Deuteromycetes

Options

A. Phycomycetes , Basidomycetes
B. Basidomycetes, Ascomycetes
C. Ascomycetes, Phycomycetes
D. Phycomycetes , Deuteromycetes

Answer

To solve the question, we need to identify two groups of fungi based on their reproductive processes: one that immediately forms a diploid cell after the fusion of haploid cells, and another that goes through a dikaryotic stage.

### Step-by-Step Solution:

1. **Understanding the Fungal Groups**:
- Fungi are classified into several groups, including Phycomycetes, Ascomycetes, Basidiomycetes, and Deuteromycetes.
- Each group has distinct reproductive characteristics.

2. **Identifying the Group that Forms Diploid Cells**:
- **Phycomycetes**: In this group, when two haploid cells (n + n) fuse, they immediately form a diploid cell (2n). This means that the diploid phase occurs directly after the fusion of haploid cells.

3. **Identifying the Group with a Dikaryotic Stage**:
- **Basidiomycetes**: In this group, after the fusion of two haploid cells, an intervening dikaryotic stage (n + n) occurs, known as the dikaryon. This means that the cells contain two nuclei from the two different haploid cells before eventually forming a diploid cell.

4. **Comparing the Options**:
- Based on the characteristics:
- **Phycomycetes** results in a diploid cell immediately.
- **Basidiomycetes** has a dikaryotic stage.
- Therefore, the correct pairing is **Phycomycetes** and **Basidiomycetes**.

5. **Final Answer**:
- The correct answer is: **Phycomycetes, Basidiomycetes**.