What is the significance of testing seed viability with 2,3,5 triphenyl tetrazolium chloride?

Testing seed viability with 2,3,5 triphenyl tetrazolium chloride (often referred to as TTC) is significant because it indicates metabolic activity within the seed. This chemical is a colorless compound that, when reduced by viable (metabolically active) cells, turns into a red pigment due to the presence of enzymes, particularly dehydrogenases. The degree of coloring directly correlates with the metabolic activity of the seed, which is essential for germination.

Metabolic activity is a vital indicator of seed viability since seeds must be alive and capable of carrying out metabolic processes to germinate successfully. The ability of a seed to utilize stored nutrients and perform respiration is essential for establishing a new plant. If a seed demonstrates minimal or no reduction of TTC and thus remains colorless, this suggests that it lacks the necessary metabolic activity for germination and is, therefore, not viable.

The other options do not relate directly to viability in the context of TTC testing. Seed color, size, and water content may provide some information about the seed's characteristics or condition, but they do not specifically reflect the metabolic processes that TTC testing assesses. Thus, the correct choice directly connects to the cellular functions that indicate a seed's ability to germ