Fertilisation, seed formation and dispersal

In a nutshell

In plants, the male sex cell is pollen and the female sex cell is an ovule. These join during fertilisation to form a seed. The seed will then germinate and form a new plant.

Fertilisation

Fertilisation happens when the nuclei of the male and female sex cells join.

Science; Plants; KS3 Year 7; Fertilisation, seed formation and dispersal

1.	Pollen (yellow circle) is the male sex cell in a plant. It will land on the stigma during pollination.
2.	A pollen tube grows from the pollen grain and down to the ovary through the style.
3.	The nucleus from the male sex cell (red circle) moves down the tube.
4.	The nucleus from the male sex cell joins the nucleus of the female sex cell (blue circle). This joining process is called fertilisation.

Seed formation

After fertilisation, the ovule develops into a seed and the ovary develops into a fruit around the seed. The seed contains an inactive embryo.

Science; Plants; KS3 Year 7; Fertilisation, seed formation and dispersal

1.	Food store	The seed has a food store containing starch that it can use to grow until it can carry out photosynthesis.
2.	Embryo	The embryo is the young root and shoot that will grow into the plant.
3.	Seed coat	The seed has a seed coat that provides protection.

Seed dispersal

Seed dispersal is the transport of seeds from their parent plant to another area. Spreading out the seeds is an important process as plants will compete with each other for light, water, space and minerals. By dispersing their seeds, the plants have a better chance of surviving.

Dispersal method	Description	Examples
Animal	Seeds are spread by animals. The animal may eat the fruit and the seeds will come out in their droppings. The seeds can also get attached the animals coat and they carry it away with them. Animals can also bury seeds in order to eat them later. During this time, the seed may have the chance to germinate.	Tomatoes, goose grass and acorns
Explosion	The seeds are contained in a pod and are released when the pod bursts.	Peas
Wind	Seeds are carried away by the wind.	Sycamore and dandelions
Drop-and-roll	The fruit falls from the plant and rolls away.	Conkers
Water	Plants that grow near water sources, like rivers, may drop their seeds into the water. The flow of the water will carry the seed away.	Coconut and willow