Types of Seed Dispersal and Its Importance

In order for new plants to grow, seeds need to be distributed to different areas away from the parent plants. A disadvantage of plants compared to animals is that plants cannot physically get up and move themselves to different places.

Seed dispersal is a very important part of nature and how plants coexist with other plants. It allows seeds from plants to be moved or dispersed to other areas where they can receive their own resources such as water, sunlight and soil nutrients. There are many methods by which seed dispersal occurs but there are a few main ways that it occurs. These methods are wind/air, water, animal, and fire. Each of these methods is specific to certain plants and they are required in order for plants to actually grow and prosper in the environment that they are put in.

Wind seed dispersal is also known as air seed dispersal. Seeds on plants that are programmed to undergo wind dispersal are very light and are somewhat similar to feathers. The unique appearance and characteristics of the leaf allow the wind to carry the seeds long distances. An example of a plant that undergoes wind seed dispersal is a dandelion. When the head of the dandelion is blown, the little feathery - type things that fly away are actually the seeds of the plant and they are actually being dispersed.

Another example of a wind dispersal plant is a maple tree. Maple trees grow seeds that are shaped like a helicopter with wings. This design of the seed permits it to make use of the wind and “flutter” far away from the parent plant. In fact, if the wind is the correct amount, some seeds can be transmitted hundreds of miles away. However, wind dispersal seeds move about in all different directions and they do not have any control over where they go and this causes most seeds to not land in areas suitable for a plant to grow. For this reason, plants such as dandelions grow many seeds to increase the chances that seeds land in suitable area to grow.

Seed dispersal can also occur with the help of water. This happens when the seeds physically float away from the parent plant in water. Mangrove trees live in estuaries, which are the areas where freshwater meets the salt water from the sea. The seeds from the mangrove trees can either fall during low tide and the seeds will begin to root. If the seeds fall straight into the water, they current will carry them away to another area. Coconuts are other seeds that are dispersed by water and end up on beaches and germinate.

Animals also are able to disperse seeds and this happens through their droppings. For example, birds in New Zealand forests eat fleshy fruit and the chemicals in their body make the coats around these seeds weaker. They are then dropped from the birds far away from where they started since birds can fly. Another method by which animals disperse seeds is through plants that have sticky seeds such as pittosporum or plants that have hooks on their seeds. These seeds then attach themselves to animals (can even hitch a ride on humans) and are carried and passed on to different places.

The final technique that is among the most important of the many ways that seed dispersal occurs is through fire. It is obvious that if there is a fire in a forest, plants cannot avoid it or get away from it. Instead, some plants have adapted to this and have allowed the seeds to survive during extreme heat conditions. There are some species of pine trees that use the heat from the fire to open the cones and release the seeds. However there is also a downside to this. If fires happen too often, the plants from the newly dispersed seeds will not have enough time to grow big enough to grow their own seeds that are ready to disperse. Another process that is similar to fire seed dispersal is explosion seed dispersal. It comes about in plants such as peas which have seed pods that dry out when the seeds are ripe and prepared. When the pods dry out, they split open and the seeds distribute among a different space.

It is clear that seed dispersal is integral to allowing plant population growth and reduction of competition between plants. In essence it permits plants to live and spread their population. In order for certain plants to undergo the specific seed dispersal processes they require in the environment they are located in, they would have had to be adapted. For example, cones on the pine trees would have had to adapt to be able to survive in fires. Not only that the pine cones make use of the fires and release the seeds when a fire is present. Plants cannot physically move themselves to different areas but seed dispersal is as good of a replacement because it authorizes the seeds from the plants to migrate to different areas. This prevents the offspring plants from competing for resources such as sunlight and water with the parent plants.

Many seed dispersal methods exist to fit the requirements by different plants such as plants that live in water as opposed to plants that live in places where fires are common and make use of it. At the end of it, seed dispersal is a key factor to all of plants which also affects all of nature.