The Tetrazolium test measures potential germination. This is most commonly used on small-seeded crop species, but we demonstrate it on large seeded crops to facilitate viewing the test. The chemical compound 2,3,5 tetrazolium chloride is a white powder, mixed with water to a range of 0.1 to 1% solution and stored in a dark bottle (to avoid light) in a refrigerator.
The living tissue in the seed (the germ or embryo) turns red within a few hours. The reaction that causes the change in color is related to the respiration rate. Red or pink tissue means that the tissue is healthy and is respiring normally, black that the tissue is respiring rapidly due to either injury or being a meristematic area, and white is dead tissue with no respiration.
This is a corn kernel changing color.