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How Flowers Become Fruits
Flowers Become Fruits
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Flowers are reproductive structures that allow many plants to make seeds and spread to new places. After pollination and fertilization, parts of the flower change dramatically instead of simply falling away. The ovary of the flower grows into a fruit, while the ovules inside become seeds. This process matters because fruits protect seeds, help with seed dispersal, and provide much of the food humans and animals eat.
Pollination begins when pollen moves from the anther to the stigma, often by wind, water, insects, birds, or other animals. A pollen tube grows down through the style and delivers sperm cells to an ovule inside the ovary. After fertilization, hormones trigger the ovary wall to thicken into the fruit wall, called the pericarp. At the same time, each fertilized ovule develops into a seed that contains a young plant embryo and stored food.
Key Facts
- Pollination is the transfer of pollen from an anther to a stigma.
- Fertilization occurs when a sperm cell from pollen joins an egg cell inside an ovule.
- Ovary becomes fruit after fertilization.
- Ovules become seeds after fertilization.
- Fruit wall = pericarp, which develops from the ovary wall.
- Number of seeds often equals the number of ovules that were successfully fertilized.
Vocabulary
- Pollination
- Pollination is the movement of pollen from the male part of a flower to the female part of a flower.
- Fertilization
- Fertilization is the joining of a sperm cell and an egg cell to form the first cell of a new plant.
- Ovary
- The ovary is the swollen lower part of the pistil that contains ovules and later develops into a fruit.
- Ovule
- An ovule is a structure inside the ovary that contains an egg cell and can develop into a seed.
- Pericarp
- The pericarp is the fruit wall that develops from the ovary wall and may become fleshy, dry, tough, or papery.
Common Mistakes to Avoid
- Thinking the whole flower becomes the fruit is wrong because the fruit usually develops from the ovary, while many other flower parts wither or fall off.
- Confusing pollination with fertilization is wrong because pollination only moves pollen, while fertilization is the joining of sperm and egg cells.
- Saying seeds turn into fruits is wrong because ovules become seeds and the ovary becomes the fruit surrounding them.
- Assuming every pollinated flower makes a fruit is wrong because pollen must be compatible, reach the ovule through a pollen tube, and successfully fertilize an egg.
Practice Questions
- 1 A flower ovary contains 8 ovules. If 6 ovules are successfully fertilized, how many seeds would you expect in the fruit?
- 2 A plant produces 40 flowers. If 75% of the flowers are successfully pollinated and fertilized, how many fruits should form?
- 3 A flower receives pollen on its stigma, but the pollen tube fails to reach an ovule. Explain whether a fruit with seeds should develop and why.