By removing water, the plant helps to reduce the seed's weight. This is useful if the seed is to be transported by the wind where any loss of weight will help to keep the seed in the air so it can be caught by a gust and blown away. Removing water helps all seeds in two further ways. It protects them in cold weather and it protects them from fungi.

Seeds are usually produced at the end of the growing season before the weather becomes harsher as winter sets in. After the seeds have been spread they may lay on or near the surface of the ground through long periods of cold weather. During this time the seeds may freeze. If a seed contained a large amount of water the water would expand as it froze and tear up and kill the tiny plant.

Fungi feed on damp plant material. If the seed with water survived the winter a mould may grow in it during the warm damp weather of spring. The mould would feed on the food store and rob the tiny plant of its nourishment. The fungus would probably feed on the tiny plant too.

So, after the dry seed lands in the soil it remains inactive or dormant through the harsh winter weather. As the weather becomes warmer in spring the seed begins to take in water. It has a little hole in it through which the water passes. The seed may take in so much water that it changes shape. For example pea seeds are wrinkly but as they take up water they swell up and become round and smooth. Just soak some dried peas overnight to see how quickly they change.

The seed needs water so that the food can dissolve and be passed to the tiny plant for growth. As the plant grows the seed coat bursts to let it out. The root grows out first so it can hold the plant in the soil and collect more water and minerals. The shoot follows later. It does not matter how the seed lands the root always grows down and the shoot always grows upwards. The plant which emerges from the seed is called a seedling.

The sprouting of the plant from the seed is called germination. It soon passes as the seedling grows quickly. The seed only carries enough food to help the seedling make its own first few leaves. When they have grown the seedling can make its own food from air, water and sunlight.