From Pollination to Fruit and Seed Formation

Hello! In the last lesson, you traced how a leaf takes in the materials for photosynthesis and transports sugars around the plant. Now we’ll turn to flowers, where flowering plants produce seeds that can grow into new plants.

This lesson follows one connected story on a labelled flower diagram: pollen reaches a flower, fertilisation takes place inside an ovule, and the flower develops seeds and fruit. Allow about 35–40 minutes, including time to study the diagrams and trace the route yourself.

Read the flower as a map

Start with the flower on the left of this diagram. Its labels tell you where pollen begins and where it needs to go.

The stamen is a male reproductive part. Its anther produces pollen grains, and its filament holds the anther up. In the diagram, the female structure is labelled the pistil. Its stigma receives pollen; below that, the style connects to the ovary, which contains ovules. Each ovule contains an egg cell. You may also see this female structure called a carpel in school diagrams.

The outer parts have roles too. Petals can attract animals that carry pollen, while sepals protect the developing flower bud. But the route we need to follow begins at the anther and ends inside an ovule—not on a petal.

Watch the flower-parts and pollination portions of FuseSchool’s Sexual Reproduction in Plants. Keep the diagram nearby so you can match what you hear to its labels.

Pollination is the transfer of a pollen grain from an anther to a stigma. An insect may carry it while visiting flowers; wind can carry pollen in other plants. Pollen can reach a stigma on the same plant (self-pollination) or on another plant of the same species (cross-pollination). In either case, arrival at the stigma is pollination, not fertilisation. The egg is still down inside an ovule.

From pollen on a stigma to fertilisation

Look again at the enlarged centre of the first diagram. A compatible pollen grain on the stigma begins to grow a pollen tube. The tube travels down through the style and reaches an ovule in the ovary. Male reproductive cells travel through the tube; the whole pollen grain does not travel down the style.

The next part of the FuseSchool video shows this hidden journey.

Fertilisation occurs when a male cell from the pollen joins with the egg cell inside an ovule. Their nuclei fuse to form a zygote, or fertilised egg. The zygote develops into an embryo—the young plant inside a seed. This is the crucial difference between the two terms: pollination places pollen on the stigma; fertilisation joins reproductive cells inside an ovule.

The detailed diagram also labels a second sperm nucleus and endosperm, which provides food for the developing embryo. You do not need those extra labels to locate fertilisation: find the ovule, then find the egg and the zygote shown inside it.

A seed inside a fruit

After fertilisation, the ovule develops into a seed, while the ovary develops into a fruit. These are different structures: the ovary surrounds the ovules in the flower, and the fruit surrounds the seeds that develop from them. A flower with several successfully fertilised ovules can form a fruit containing several seeds.

A cherry makes the relationship particularly clear:

At the left of the cherry diagram, find the ovary and the structure it contains. The label “seed (ovule)” identifies the structure before it has developed into a seed: at that stage, ovule is the accurate name. At the right, the fleshy part and hard woody layer belong to the fruit; the seed is inside the hard layer. Thus, the whole cherry is not a seed, and the seed is not the whole fruit.

A seed contains the embryo, a protective seed coat, and a source of nourishment for early growth. Under suitable conditions, the embryo can germinate and grow into a seedling, as shown at the far right of the first diagram. Not all fruits are fleshy like cherries: in biology, fruit means a structure developing chiefly from a flower’s ovary, whether it is fleshy or dry.

Trace it on the diagram

Return to How flowering plants reproduce and follow the labels in order:

1. Locate the anther, which produces pollen, and the stigma, where a pollen grain lands. That transfer is pollination.
2. Follow a pollen tube down the style into an ovule within the ovary.
3. Find the egg and then the zygote. Their positions show where fertilisation happens and where the embryo begins.
4. Compare the labelled flower with the later stages: the ovule becomes a seed, and the ovary becomes a fruit.

When reading or drawing a flower diagram, keep two pairs separate: anther versus stigma (pollen source versus landing place), and ovary versus ovule (the containing structure versus the structure that becomes a seed). Those distinctions make the entire sequence easier to explain.

Key takeaways

Pollination brings pollen from an anther to a stigma. A pollen tube then grows to an ovule, where a male cell joins an egg cell in fertilisation. The fertilised ovule develops into a seed containing an embryo, and the ovary develops into a fruit around the seed or seeds.

This completes our look at plant structures. Next, the course turns to chemistry and uses the particle model to explain solids, liquids, gases, and changes of state.