Which of the following is known as triple fusion?

Options

A. Fusion of male gamete with female gamete to form zygote
B. Fusion of secondary nucleus with male gamete
C. Fusion of polar nuclei to form secondary nucleus
D. Fusion of generative nucleus with tube nucleus.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Concept of Fusion in Reproduction:**
- In plant reproduction, particularly in angiosperms, fertilization involves several key processes, including the fusion of gametes.

2. **Identifying Types of Fusion:**
- **Syngamy:** This is the fusion of a male gamete (sperm) with a female gamete (egg) to form a zygote. This process is not referred to as triple fusion.
- **Triple Fusion:** This specifically refers to the fusion of the secondary nucleus (formed by the fusion of two polar nuclei) with a male gamete. This results in the formation of the triploid endosperm nucleus.

3. **Analyzing the Options:**
- **Option A:** Fusion of male gamete with female gamete to form zygote (syngamy) - Incorrect.
- **Option B:** Fusion of secondary nucleus with male gamete - This is the definition of triple fusion.
- **Option C:** Fusion of polar nuclei to form secondary nucleus - This is a precursor to triple fusion but not triple fusion itself.
- **Option D:** Fusion of generative nucleus with tube nucleus - This occurs during double fertilization and is not related to triple fusion.

4. **Conclusion:**
- Based on the analysis, the correct answer to the question "Which of the following is known as triple fusion?" is **Option B: Fusion of secondary nucleus with male gamete.**