How Plant Parts Work

Water poured onto soil can enter a sunflower through its roots. Minerals dissolved in that water enter too. The stem carries water and minerals towards the leaves.

Food takes other routes. Leaves make sugar using energy from sunlight. Some of this food moves through the stem to growing shoots, roots or seeds.

Try tracing these routes with words. Start a water route at the roots. Start a food route at the leaves. The routes connect plant parts, but the parts do not take turns doing their jobs.

A carrot plant stores food in its thick root. The plant made that food. It did not take ready-made sugary food from the soil.

Roots have other jobs too. They take in water and minerals and help hold a plant in place. Grass has many thin roots. A carrot has a large main root with smaller roots branching from it.

Most roots grow below ground. Some plants also have roots above ground. A root's job is a better clue than a rule that every root must be underground.

A leaf needs more than sunlight to make sugar. It also uses water and carbon dioxide, a gas from the air. Sunlight supplies energy for the food-making process, called photosynthesis.

Chlorophyll is a green substance that helps a leaf use light. Many leaves have a broad surface that catches light, but leaf shapes vary.

Leaves are common food-making parts. They are not the only parts that can make food. In some plants, green stems do this too. Losing leaves does not mean that every kind of plant has lost its only way to make food.

Flowers contain parts that help a flowering plant make seeds. Many flowers attract animals that move pollen while visiting them.

Inside a flower are small structures called ovules. After fertilisation, an ovule can develop into a seed. The seed contains a young plant. Fruit grows around the seeds and can help protect them or carry them elsewhere.

A seed may later begin growing when conditions are suitable. It needs water, air and suitable warmth. Once the new plant has green leaves, those leaves can use light to make food.

Water and sugary food travel through different sets of pathways inside a plant. Water and minerals move from roots towards leaves. Food moves from places where it is made to places where it is used or stored.

Food can travel upwards to a growing shoot or downwards towards roots. Its route depends on where it is needed.

Water also leaves the plant. Some water in leaves becomes water vapour and escapes through tiny openings. This loss helps pull more water up from below. A plant does not suck on its stem as a person sucks on a drinking straw.