Tetrazolium Testing

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Tetrazolium (TZ) testing is a rapid method (can be finished within less than two days) for the evaluation of seed viability. This method has been widely used by seed scientists to assess germination potentials, to determine the extent of seed damage, and to evaluate seed vigor and/or other seed lot problems.

The principle of TZ testing is based on the presence of dehydrogenase activity in viable seed tissues during the respiration process. Dehydrogenase can catalyze the colorless 2,3,5 triphenyl tetrazolium chloride solution into a red dye formazan (Figure 1). Therefore, living tissues of seeds that imbibe tetrazolium chloride will be stained red, while dead tissues will retain their natural color (Figure 2).

Figure 1. The principle of TZ testing (Elias et al., 2012).

Figure 2. Examples of TZ testing for seed viability test (Elias et al., 2012). (Left two: viable seeds; Right two: non-viable seeds)

A standard TZ testing assay involves the following steps:

  • Preparation of dry seed. The seed coats of many species are best to be treated by mechanical abrasion so that water or solutions can penetrate into the interior tissues of the seed.
  • Moistening. This step aims to hydrate the seeds to activate the respiratory enzymes and to soften the tissues for cutting and piercing.
  • Preparation for staining. Cut or pierce the seed to facilitate the absorbing of TZ solution by internal tissues.
  • Staining. Soak the cut seeds in TZ solution for certain periods of time.
  • Evaluation of staining patterns. Examine the seed for a color change in the embryo.

Lifeasible, as a global company specialized in plant biotechnology, offers innovative and reliable solutions for the evaluations of seed viability. Our skilled seed scientists and experts have contributed decades of dedicated work for the exploration and optimization of seed viability test. We proudly offer competitive short-turn-around and high-quality TZ testing service. Noticeably, we offer customized services to adapt to specific species and different research goals. Our tailored protocols guarantee the optimal experimental conditions, including imbibition time, moistening time, cutting manner, TZ concentration, staining time and temperature, and so on. We are devoted to providing our worldwide customers with our featured technologies, service plans, collaboration options and more.


  1. Elias, S. G., Copeland, L. O., Mcdonald, M. B., and Baalbaki, R. Z. (2012). Seed Testing: Principles and Practices. Michigan State University Press.
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