Viability of the seed is tested with

Options

A. triphenyl tetrazolium chloride
B. Indole acetice acid
C. Mercuric chloride
D. 2,4-D

Answer

### Step-by-Step Solution

1. **Understanding Seed Viability**:
- Seed viability refers to the ability of a seed to germinate and develop into a new plant. It is a crucial factor in agriculture and horticulture as it determines the potential success of planting.

2. **Importance of Testing Seed Viability**:
- Seeds have a certain lifespan during which they can germinate. After this period, they lose their viability and cannot sprout. Testing seed viability helps in assessing whether seeds can produce healthy plants.

3. **Methods to Test Seed Viability**:
- There are various methods to test seed viability, but one of the most common and effective methods involves the use of specific chemical compounds.

4. **Identifying the Correct Compound**:
- The question provides several options:
- A) Triphenyltetrazoleum chloride
- B) Indoleacetic acid
- C) Mercuric chloride
- D) 2,4-D
- Among these, triphenyltetrazoleum chloride (TTC) is known for its use in viability testing.

5. **How Triphenyltetrazoleum Chloride Works**:
- TTC is a colorimetric reagent that can indicate seed viability. When seeds are soaked in a 0.2% solution of TTC and cut into slices, viable seeds will show a red color due to the reduction of TTC to formazan, indicating that the tissues are alive and capable of germination.

6. **Evaluating Other Options**:
- **Indoleacetic acid**: This is a plant growth regulator (auxin) and does not test seed viability.
- **Mercuric chloride**: This is used as a sterilizing agent and does not indicate seed viability.
- **2,4-D**: This is another plant growth regulator and does not serve the purpose of testing seed viability.

7. **Conclusion**:
- Based on the analysis, the correct answer to the question "Viability of the seed is tested with" is **A) Triphenyltetrazoleum chloride**.