Tetrazolium (TZ) Testing

After the seed conditioning phase was complete, I proceeded to test the seed viability. Tetrazolium tests are performed at the ISU Seed Testing Lab. In this test, seeds are imbibed overnight, then pierced the following day and soaked in a tetrazolium solution. The solution is then absorbed through the piercing, tinting the seed. 

Because of the limited number of seed available for the project, two replications of 50 seeds were performed for each species in lieu of the typical 100 seeds per replication.

M. bradburiana TZ test results.

V. lettermannii TZ test results.

Preliminary results were reported on January 23, 2015. The official report was published on January 26, 2015. The results were as follows:

  • M. bradburiana: 72% viable seed reported.
  • V. lettermannii: 2% viable seed reported.

The cause for poor embryo development in this batch of V. lettermanni is unknown. However, due to the low viability of V. lettermannii, a replacement species must be used for this study.