Substance which induces the fusion of protoplast, is/are

Options

A. Polyethylene glycol
B. `NaNO_(3)`
C. `Ca^(++)` ions at high pH
D. All of the above

Answer

To answer the question about the substances that induce the fusion of protoplasts, we can break down the information provided in the video transcript step by step.

### Step-by-Step Solution:

1. **Understanding Protoplast Fusion**: Protoplast fusion is a technique used in biotechnology where the cell wall of plant cells is removed, leaving behind the protoplast (the living part of the cell). This allows for the fusion of two protoplasts to create a hybrid cell.

2. **Identifying Substances Involved**: The transcript mentions several substances that are involved in the fusion of protoplasts:
- **Polyethylene Glycol (PEG)**: A chemical that plays a crucial role in the fusion process.
- **Sodium Nitrate (NaNO3)**: Another chemical that contributes to the fusion.
- **Calcium Ions (Ca²⁺)**: These ions enhance the adhesion of protoplasts during the fusion process.

3. **Mechanism of Action**:
- **PEG**: It induces tight adhesion of protoplasts due to electrostatic forces. It helps in bringing the protoplasts closer together, facilitating fusion.
- **Sodium Ions**: They induce localized realignment of the lipoproteins in the membrane, which is essential for the fusion to occur when the protoplasts come into contact.
- **Calcium Ions**: They act as a molecular bridge between the negatively charged PEG and the proteins in the membrane, enhancing adhesion and promoting fusion.

4. **Conclusion**: Since all the mentioned substances (PEG, sodium nitrate, and calcium ions) contribute to the process of protoplast fusion, the correct answer to the question is "all of the above."

### Final Answer:
The substances which induce the fusion of protoplast are:
- Polyethylene Glycol (PEG)
- Sodium Nitrate (NaNO3)
- Calcium Ions (Ca²⁺)

Thus, the correct option is **all of the above**.

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