Slide 1
A dormant seed can be alive without germinating
A dormant seed does not germinate immediately even when some conditions seem suitable. Dormancy helps time the start of a plant's growth.
More to Read
Waiting because soil is simply dry differs from internal dormancy. Researchers distinguish these causes because adding water solves one problem but may not remove the other barrier.
Slide 2
The seed coat can block water or growth
Some seeds have coverings that restrict water entry or embryo growth. A change to those coverings can permit germination.
More to Read
Other seeds have physiological controls inside the embryo, so opening the coat is not always sufficient. Similar outward stillness can arise from different mechanisms requiring different seasonal cues.
Slide 3
Moist cold can signal that a season has passed
Some seeds respond to a period of moist cold before germinating. The sequence can reduce growth during an unsuitable season.
More to Read
Cold treatment is called stratification in propagation work. Its required duration and temperature differ among species, so a winter cue should not be generalized into one universal seed recipe.
Slide 4
Seeds emerging at different times spread the risk
Seeds from one plant need not all germinate together. A persistent soil seed bank can distribute emergence across different opportunities.
More to Read
That strategy can leave some seeds available after a poor growing year. It also means the plants visible in a season are only part of the population's potential future.
Slide 5
A short germination test can miss a living seed
Seed researchers distinguish a dead seed from a viable one that has not yet germinated. A failed short test cannot always decide between them.
More to Read
Carefully chosen temperatures, light conditions and pretreatments help reveal germination requirements. A test must fit the species, rather than assuming all living seeds should sprout on the same timetable.
Sources
- Germination testing dormancy
Royal Botanic Gardens Kew
- Revealing the hidden mysteries of holly
Royal Botanic Gardens Kew