The TTC-technique might not appropriately test the physiological stage of plant tissues
Seeds are very attractive and convenient for molecular genetic studies that challenge principal biological phenomena related to the initiation and suppression of growth (e.g., germination and dormancy, respectively). The number of reports in this field is rapidly expanding. Seed dormancy is a widely misinterpreted biological attribute. One of the main reasons is the general neglect of reliable dormancy assays; often, the sole criterion of current dormancy assays is the total germination of a seed population after a defined period of time. This is a very insensitive and inaccurate method, particularly when comparing dormancy levels of seeds from different genotypes, seeds subjected to different treatments, or seeds originating from different environments. Other seed parameters are far more useful. Furthermore, before undertaking comprehensive molecular and biochemical studies to elucidate the underlying mechanisms of dormancy of a given species, it is pivotal to determine the general types or categories of dormancy that are imposed and whether these are influenced by the external environment. Research strategies should be adjusted to this. In order to distinguish dead from dormant seeds, a viability test should be developed. This chapter addresses in a very general way these pitfalls in dormancy research with a focus on current plant model systems in molecular genetics, such as Arabidopsis thaliana and Medicago truncatula.