Which chemical is used to test the viability of seeds?

The chemical that is commonly used to test the viability of seeds is 2,3,5 triphenyl tetrazolium chloride (often abbreviated as TTC). This compound is a colorless dye that acts as a redox indicator. When applied to seeds, viable seeds that are alive and capable of growth will reduce the TTC to formazan, which produces a red or pink coloration. This color change indicates metabolic activity, confirming that the seeds are alive and capable of germination.

In the context of the other chemicals listed:

• Potassium nitrate is often used in plant physiology and agriculture as a fertilizer and may influence plant growth, but it does not specifically indicate seed viability.

• Calcium chloride has applications in various fields, including plant growth and preservation, but it does not serve as a viability test for seeds.

• Silver nitrate is primarily used for its antimicrobial properties and in various chemical reactions and does not indicate seed viability.

Thus, the use of 2,3,5 triphenyl tetrazolium chloride is specifically focused on determining the potential for seed germination, making it the correct choice for assessing seed viability.