Find out why seed dispersal is important and how different plants disperse their seeds to reproduce...
When a flowering plant is fertilised, seeds grow inside the ovary of the flower. The ovary then becomes the fruit of the plant, which contains the seeds. In order to reproduce and create new plants, the parent plant needs to disperse their seeds so that they can be fertilised. This means that the seeds need to travel away from the parent plant.
Seed dispersal is important for the survival and success of plants. If all seeds germinated in the same place near the parent plant, there would be too much competition for sunlight and nutrients from the soil for all the plants to survive. It also allows plants to germinate in new environments where conditions might be more favourable. This maximises the chance of survival for the plant.
Another reason why seed disperal is important is that it helps support the health and diversity of ecosystems. Animals benefit from eating the fruit of the plants, which then benefits the plant too because the animal spreads the seeds. This mutually-beneficial system helps support ecosystems by contributing to the survival of both plants and animals.
There are several different ways in which plants can disperse their seeds, including by wind, by animals, by explosion, by water and by gravity.
The wind blows the seeds from the plant and carries them on the breeze to a different location. Plants that disperse their seeds by wind include grasses, dandelions, maple trees, pine trees, willow trees and orchids. Some of these plants (such as dandelions and willow trees) have very lightweight seeds that are easily carried on the wind. Others, like maple trees, have seed pods that have wing-like structures which allow the seeds to be carried away from the parent plant.
Maple seeds are encased in cases shaped like helicopter blades to help them travel on the wind.
There are several ways in which animals can help plants disperse their seeds. Many plants have fruits that animals eat, such as raspberries, strawberries, apples, tomatoes and holly. The animals eat the seeds in the fruit, which then pass through the animal in their droppings, placing the seeds in a new location. This is known as internal seed dispersal.
Other plants have sticky seeds that stick to the fur of animals, such as burdock fruits and cocklebur. This is known as external seed dispersal.
Other plants have seeds that animals store, such as the acorns from oak trees. Squirrels take the acorns and store them underground, ready to eat later. Sometimes, these acorns are forgotten about, or the squirrel can't return to eat them, giving the acorn the chance to grow into a new plant.
Birds eat berries then disperse the seeds through their droppings
The fruits of some plants explode, flinging the seeds far away from the parent plant. For example, bean pods dry out and get tightly stretched around the beans inside. Eventually, they dry out and fling the beans through the air.
The sandbox tree (which is also known as the dynamite tree) grows large fruits that explode with a bang, sending its seeds flying away from the parent plant at high speeds!
Other plants that use explosion to disperse their seeds include witch hazel, geraniums, violets and buttercress.
Beans explode out of their pods when they dry out
Some plants that live near water have seeds that can float. These seeds then get carried away on the water to new places. Coconut trees, mangroves and water lilies are all examples of plants that disperse their seeds by water.
A coconut floating in the water
Some seeds simply fall to the ground when their fruits get too heavy to be supported by the plant and often rely on gravity to help them roll away to a new location away from the parent plant. Apple, avocado and mango trees are all examples of plants that can use gravity for seed dispersal, although these seeds are often then transported by animals once they have fallen to the ground.
A mango fruit fallen on the ground by gravity
