Warm Germination

Association of Official Seed Analysts (AOSA) Germination Definition: The emergence and development from the seed embryo, those essential structures, which, for the kind of seed in question, are indicative of the ability to produce a normal plant under favorable conditions.

What are the essential structures?
Depending on the plant family, the plant shoot, root(s), hypocotyl, epicotyl, leaf in teh coleoptile, etc. are evaluated to ensure the seedling will produce at normal plant.

What are favorable conditions in a seed laboratory?
Controlled laboratory conditions, which have been shown to result in a maximum germination percentage for each species.  Test duration, temperature, light, dormancy breaking methods, media, and kind of moisture are the primary variables used to define favorable or optimal conditions for each species.
  • Test duration: 3 to 42 days depending on species
  • Temperature (degree celsius): 20, 20-30, 15-25, 15-30, 20-35, and 15 are some of the more commonly used temperatures
  • Light: Light is typically required, however there are instances where dark gives higher results
  • Dormancy breaking: pre-chill, KNO3 , scarification, and GA3 are common methods of breaking dormancy
  • Media: planting on top of blotter, rolled towels and pleated paper are commonly used
  • Kind of moisture: H2O, or very low concentrations of KNO3 and GA3

How are the planted seeds evaluated at the end of the test?  
  • Normal seedling: a seedling with all of the essential structures required to make a normal plant
  • Abnormal seedling: a seed that has sprouted, but does not have proper development of all of the essential structures
  • Hard or dormant seeds: viable seeds that have not germinated at the end of the germination test.
    • Hard seeds do not absorb water during germination test
    • Dormant: determined at the end of the germination test by use of Tetrazolium (TZ)
  • Dead seeds: seeds that are dead