Life Cycle of a Plant KS2

A plant life cycle describes the stages a plant passes through as it grows, reproduces and begins the cycle again. At KS2, children learn about the life cycle of flowering plants, including pollination, fertilisation, seed formation, seed dispersal and germination.

They may also explore plant reproduction at KS2, comparing sexual reproduction in flowering plants with the different ways some plants reproduce asexually.

What are the stages of a plant life cycle?

The exact life cycle varies between different species, but the life cycle of a flowering plant usually includes the following stages:

1. Seed: The life cycle begins with a seed containing a young plant, known as an embryo.
2. Germination: When conditions are suitable, the seed begins to grow.
3. Growth: Roots grow downwards and a shoot grows upwards towards the light.
4. Flowering: The mature plant produces flowers containing its reproductive organs.
5. Pollination: Pollen is transferred from the anther to the stigma.
6. Fertilisation: Male and female sex cells join inside the ovary.
7. Seed formation: The fertilised ovules develop into seeds, often inside a fruit.
8. Seed dispersal: The seeds are carried away from the parent plant.

When a dispersed seed reaches a suitable place and begins to germinate, the plant life cycle starts again.

The life cycle of a lemon tree

How does a seed germinate?

Germination is the process through which a seed begins to grow into a new plant. Most seeds need water, oxygen and a suitable temperature before germination can take place.

The seed absorbs water and swells. Its outer coat splits, allowing the first root to grow down into the soil. A shoot then grows upwards. As the first leaves develop, the young plant can begin making its own food through photosynthesis.

Seeds do not usually need light to begin germinating, although the young plant will need light once its leaves emerge.

What is the purpose of a flower?

The flower is the reproductive part of a flowering plant. It contains the male and female structures needed for sexual reproduction and helps the plant produce seeds.

The main reproductive parts of a flower are:

• Stamen: The male part of the flower, made up of the anther and filament.
• Carpel: The female part of the flower, made up of the stigma, style and ovary.
• Anther: Produces pollen containing the male sex cells.
• Stigma: The sticky surface that receives pollen.
• Ovary: Contains the ovules, which can develop into seeds after fertilisation.
• Petals: Often brightly coloured to attract pollinating insects.
• Nectary: Produces nectar that attracts animals to the flower.

The parts of a flower

How do flowering plants reproduce sexually?

Sexual reproduction in flowering plants involves pollen from the male part of a flower reaching the female part of a flower. It includes the processes of pollination and fertilisation.

Pollination

Pollination occurs when pollen is transferred from an anther to a stigma. Pollen can be carried between flowers by insects, other animals, wind or, in some species, water.

Bees and other insects are attracted to flowers by their petals, scent and nectar. As an insect feeds, pollen from the anthers may stick to its body. When it visits another flower, some of this pollen can be transferred to the stigma.

Some plants can self-pollinate, while others require pollen from another plant of the same species.

Fertilisation

After a pollen grain lands on a suitable stigma, a pollen tube grows down through the style towards the ovary. The male sex cell travels through this tube and joins with a female sex cell inside an ovule.

This joining of the male and female sex cells is called fertilisation.

Seed and fruit formation

Following fertilisation, the fertilised ovules develop into seeds. The ovary may develop into a fruit that protects the seeds. The petals and other flower parts often dry up and fall away.

The seeds can then be dispersed, allowing new plants to grow away from the parent plant.

How are seeds dispersed?

Seed dispersal helps seeds spread to new locations. This reduces competition between the young plants and their parent for light, water, nutrients and space.

Seeds can be dispersed in several ways:

• By wind: Lightweight or winged seeds, such as dandelion and sycamore seeds, are carried through the air.
• By animals: Seeds may stick to fur or be eaten inside fruits and later deposited elsewhere.
• By water: Buoyant fruits and seeds can float to new locations.
• By explosion: Some seed pods burst open and scatter their seeds.
• By gravity: Fruits may fall from the parent plant and roll away.

An example of a flowering plant life cycle

A lemon tree provides a clear example of the life cycle of flowering plants at KS2:

1. A lemon seed germinates in suitable conditions.
2. The seed grows roots, a shoot and leaves.
3. The young plant develops into a mature lemon tree.
4. The tree produces flowers.
5. The flowers are pollinated.
6. Fertilisation takes place inside the flowers.
7. The ovaries develop into lemons containing seeds.
8. The seeds can grow into new lemon trees.

How do plants reproduce asexually?

Some plants can reproduce asexually. This means that only one parent plant is needed and there is no joining of male and female sex cells.

Plants produced through asexual reproduction are genetically identical to the parent plant. They are known as clones.

Bulbs

Plants such as daffodils, tulips and onions can produce new bulbs beside the parent bulb. Each bulb can grow into a new plant.

Tubers

Potatoes grow underground storage structures called tubers. New shoots can grow from the buds, or “eyes”, on a potato tuber.

Runners

Strawberry plants produce horizontal stems called runners. These grow away from the parent plant and form new plantlets where they touch the soil.

Cuttings

Some plants can be reproduced from a cutting taken from a stem, leaf or root. When placed in suitable conditions, the cutting may grow new roots and develop into another plant.

Sexual and asexual reproduction in plants

KS2 children may be asked to compare sexual and asexual reproduction in plants.

Sexual reproduction	Asexual reproduction
Usually involves male and female sex cells	Only one parent plant is needed
Includes pollination and fertilisation	Does not involve pollination or fertilisation
Produces genetically varied offspring	Produces genetically identical offspring
Usually produces seeds	Can involve bulbs, tubers, runners or cuttings

Teaching the life cycle of a plant at KS2

Practical activities can help children understand the different stages of a plant life cycle. Your class could:

• grow seeds and record changes in a plant diary
• dissect and label the reproductive parts of a flower
• investigate the conditions needed for germination
• sequence diagrams showing the life cycle of a flowering plant
• compare different methods of seed dispersal
• observe strawberry runners, bulbs or potato tubers
• compare sexual and asexual reproduction
• create an annotated plant life cycle diagram

Frequently Asked Questions

What is the life cycle of a plant?

The life cycle of a plant is the series of stages it passes through as it grows and reproduces. A typical flowering plant life cycle includes seed, germination, growth, flowering, pollination, fertilisation, seed formation and seed dispersal.

What do children learn about plant life cycles at KS2?

At KS2, children learn how flowering plants reproduce, including the roles of pollination, fertilisation, seed formation and seed dispersal. They may also compare sexual reproduction with asexual reproduction in plants.

What is pollination?

Pollination is the transfer of pollen from an anther to a stigma. It may be carried out by insects, other animals, wind or water.

What is the difference between pollination and fertilisation?

Pollination is the transfer of pollen to a stigma. Fertilisation happens afterwards, when a male sex cell from the pollen joins with a female sex cell inside an ovule.

What does a seed need to germinate?

Most seeds need water, oxygen and a suitable temperature to germinate. Once the shoot and leaves emerge, the young plant also needs light to grow successfully.

How do plants reproduce asexually?

Plants can reproduce asexually through structures such as bulbs, tubers and runners. Some plants can also grow from cuttings. The new plants are genetically identical to the parent plant.

Explore more KS1 and KS2 plant resources, or visit our Human Life Cycle KS2 guide for information about human growth and development.