Plant Science - Seed Adaptations Flashcards
What is the radicle?
Embryonic root
What is the Cotyledons?
Stores food for embryo and photosynthesis after germination
What is the Endosperm?
Food store for embryo
What is the Plumule?
Embryonic shoot
What is the Embryo?
Structure which grows into a new plant
What is the Micropyle?
Hole where water enters the seed
What is the Testa?
Seed coat, protects seed contents
What do seeds need to germinate?
Correct temperature
Oxygen
Any dormancies broken
Water
Name the ways seed and fruit can be dispersed
Wings or fluffy attachments which catch the wind
Hooks which catch fur
Tasty flesh or tissue that encourages animals to eat or carry away
Ability to float away by water
Ability to throw seed away from plant.
Which adaptation helps avoid seeds germinating where they are shaded by other plants or buried too deeply underground?
Requirement for light
True or False: Cotyledons of plants always look like the true leaves.
False, not all species bring their cotyledons above ground when they germinate.
Describe the dormancy conditions of chemical inhibition?
Compounds in seed or fruit prevent germination
Describe the dormancy conditions of an immature embryo?
Needs to further develop before germination
Describe the dormancy conditions of a hard seed coat?
Prevents seed taking in water and exchanging gases
How is the hard seed coat dormancy broken?
Soaking
Scarification
How is the chemical inhibition dormancy broken?
Stratification
Washing
How is the immature embryo dormancy broken?
After-ripening
Stratification
What is the role of a seed to an embryo?
Store carbohydrates and proteins as food
Benefits of growing from seed - name three?
Way to propagate annuals
Easy to propagate large numbers of plants
Some species cannot be propagated vegetatively
Cheaper than buying plants
Cheaper than laying turf
In what conditions should orthodox seeds be stored?
Cold conditions once dried.
In what conditions should recalcitrant seeds be stored?
Cool and moist conditions.
What is stratification?
The process of subjecting seeds to a period of warm, moist conditions or cold, moist conditions that mimic those of natural, seasonal cycles.
True or False: Germination requirements and dormancy mechanisms allow germination of seeds to take place over a period of time, prevent seeds from germinating at inappropriate times and facilitate the formation of soil seed banks.
True
Which seed adaptations give weedy species an ecological benefit?
Effective dispersal methods
Large volumes of seed
Dormancy that allows germination over time
Describe the stages of stratification for Fraxinus excelsior (European ash)
- Soak seeds
- Put in a plastic bag filled with moist compost
- Put in a propagator for 1-3 months at 20-24oC
- Put in fridge for 2-3 months at 5oC
- Sow seeds
