A mitogen of plant origin is

Options

A. Colchicine
B. Epidermal growth factor
C. Cytokinin
D. Lymphokine.

Answer

To determine which of the given options is a mitogen of plant origin, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Mitogen**:
- A mitogen is a substance that stimulates or induces mitosis (cell division).

2. **Analyzing the Options**:
- **Option A: Colchicine**
- Colchicine is known as a potent mitosis inhibitor. It prevents mitosis by inhibiting spindle formation. Since it inhibits mitosis rather than inducing it, colchicine cannot be classified as a mitogen.
- **Conclusion**: Incorrect option.

- **Option B: Epidermal Growth Factor (EGF)**
- EGF is a protein that promotes cell division and proliferation. However, it is derived from animal sources, specifically from kidney cells and submaxillary glands. Although it acts as a mitogen, its origin is not plant-based.
- **Conclusion**: Incorrect option.

- **Option C: Cytokinin**
- Cytokinins are plant hormones that promote cell division and are classified as plant growth regulators. The name "cytokinin" is derived from "cytokinesis," indicating their role in cell division. Since they are produced in plants and induce mitosis, they are indeed mitogens of plant origin.
- **Conclusion**: Correct option.

- **Option D: Lymphokinin**
- Lymphokinin is similar to cytokinin but is secreted by T cells in animals. It promotes cell proliferation and immune responses. Since it originates from animal cells, it cannot be considered a plant mitogen.
- **Conclusion**: Incorrect option.

3. **Final Answer**:
- The mitogen of plant origin is **Cytokinin**.