Reproduction In Plants. Flashcards
(39 cards)
What is a seed?
A seed is a fertilized mature ovule.
There are, however, notable differences between seeds of different species. Name the differences.
Seeds are of different sizes, shapes, and colors depending on plant species.
Why is the slowing down of life processes important?
This is important for the plant to be able to survive unfavorable environmental conditions because the seed germinates only when environmental conditions become conducive to growth.
What slows down the life processes in seeds?
When the seed is dormant, life processes inside the seed are slowed down.
What are the parts of the male reproductive system and female reproductive system in the parts of a flower?
- Male reproductive system = anther and filament.
- Female reproductive system = stigma, style, ovary and, ovule.
Name the processes of plant reproduction (in order).
- Pollination.
- Growth of pollen tube.
- Fertilization.
- Fruit formation.
- Seed dispersal.
- Germination or Plant growth.
What is pollination and what pollinates?
Pollination is the transfer of pollen from anther to stigma. Pollination can be by insects (e.g. bees) or wind.
Name the parts pollen travels through to reach its destination?
Pollen travels from the stigma, down the style, and into the ovule of the plant.
Why does a pollen tube grow?
A pollen tube develops to carry the pollen downward.
Define fertilization (plant reproduction).
Fertilization means the nucleus of the male gamete (pollen) fuses with the nucleus of the female gamete (ovule) to form a seed.
Where do seeds develop?
The seeds develop in the ovary, which later on becomes the fruit.
What causes fruit formation?
The ovary ripens and forms a fruit. The fruit may contain a single seed or multiple seeds.
Define seed dispersal and what can disperse seed?
Seed dispersal is the movement of seeds away from the parent plant by wind (e.g. dandelion), animal (e.g. fur, eaten), or explosion (e.g. msasa).
Define germination or plant growth.
If the seed is embedded in the right kind of soil, it will germinate. A new plant grows out of the seed. A stem reaches upward, and roots go downward into the soil.
What conditions do seeds need to germinate?
Seeds germinate when there is warmth, water, and oxygen, they do not need light to germinate because they are underground.
What are the processes of germination?
- The seed rapidly absorbs water and then the seed coat or testa splits.
- The radical (first root) grows downwards into the soil. The plumule (first shoot) straightens and pushes above the soil.
- The first leaves emerge and photosynthesize.
- Soon new leaves and roots form, establishing the plant, and the cotyledons fall off.
Name the 3 external parts of a seed.
- Testa (seed coat).
- Hilum.
- Micropyle.
What is the testa?
The testa is the tough waterproof covering of a seed; protects the embryo and the food storage.
What is the hilum?
The hilum is a large oval scar, that was once the place of attachment of the young seed to the ovary wall.
What is the function of the micropyle?
The micropyle is to be an entrance through water and oxygen enter the seed for germination.
Name the 7 internal parts of a seed
- Testa (seed coat).
- Plumule (shoot system).
- Radical (root system).
- Cotyledon (food storage).
- Micropyle.
- Hilum.
- Embryo (plumule + radical).
What is the embryo and what does it comprise of?
The miniature plant found inside the seed: it comprises of three parts (the radicle, epicotyl and hypocotyl, and plumule).
What are cotyledons?
The first true leaf (monocotyledon) or set of leaves (dicotyledons) that provide food for the seedling.
Where do the cotyledons access food from and how dow long do they do this?
They access food from the seed until true leaves develop and start to photosynthesise.
