Since plants are not mobile like other living beings, they depend on various other methods to reproduce and spread their species. They depend on other living or non-living carriers to reproduce by dispersing their seeds. If you have been curious about plant reproduction, then here is the answer.
Plant reproduction is carried out by seeds. Usually, in the case of trees that produce fruits, the seeds are covered by flavorful fruits that then make it possible for carrying out the reproduction of the trees by planting them in the soil. However, many trees also do not bear fruits. For such trees, the common ways in which seeds are dispersed are through the wind, water, or animals and even fires.
1. Seed Dispersal by Wind
The best example of seed dispersal by wind is the example of dandelion. You can experiment it yourself – just blow the dandelion head and see its seeds floating away with the wind. The seeds scatter everywhere, and the ones that fall at places suitable for growth are the ones that grow into a plant. Also, Maple trees have “helicopter” seed pods that fall slowly and can blow further in the wind.
One of the most unusual forms of seed dispersal by wind is of the tumbleweed. In this case, the whole plant without the roots gets blown away by the wind and continues the process of plant reproduction.
2. Seed Dispersal by Fire
Pine cones are an example of a “fruit,” which isn’t edible. It’s still a cluster of seeds that will fall, perhaps roll, and potentially end up far from the tree. Of course, it’s not as effective as a fruit that’s eaten/pooped elsewhere or buried by a squirrel, like a berry or an acorn.
But many pine cones only open and “disperse” seeds in conditions such as a fire. The seeds aren’t necessarily dispersed and grown while the “parent” is alive, but they’re very successful at recolonizing after fires. Interestingly, some species of pine cones mandatorily require fire to crack open and spill the seeds.
Other trees that utilize this method for their seed dispersal include eucalyptus and Banksias. However, these trees require a specific intensity and timing of fire for spilling the seeds. In the case of a lot of fires, pines and other such plants do not get enough time to grow new trees.
3. Seed Dispersal by Water
Numerous plants are grown in conditions where there are less land and more water. Mangrove trees grow in estuaries – where fresh and salt waters are mixed. The seeds from the mangrove trees are carried away by the tide and dispersed for further reproduction. However, in case the seeds from the mangrove trees fall in low tide areas, they can start rooting in the soil, and a new plant is born.
Kowhai trees also use the same mechanism for seed dispersal. Their seeds are covered by a hard material that helps them keep afloat. They travel down the streams and rivers and start reproducing the tree when required conditions are met. This is the reason why we can usually find kowhai trees along the stream banks.
4. Seed Dispersal by Explosion
This is, by far, one of the most exciting methods of seed dispersal by the trees. The explosion in this method refers to the dry seeds dropping down from the trees and splitting open. Plants like peas, flax, and gorse produce seeds in a pod. These seedpods dry out after the seed is ripe and is ready to reproduce. The dry seedpods then fall from the trees and split open. This results in their seeds scattering on the ground, which leads to the growth of more of such trees.
5. Seed Dispersal by Animals
Besides eating the fruits and pooping the seeds into the soil, seed dispersal by animals is also carried out without fruits. Some seeds have hooks or tentacles that can help seeds attach to the body of animals. These seeds might attach to the fur, skin, or feathers of the animals and get dropped elsewhere.
Trees grow slowly but last a long time. Some of the trees can be successful in doing many things slowly, such as dispersing seeds within a short distance. Berries and other smaller plants are less likely to survive the winter and reproduce again. Hence, spreading their seeds widely helps ensure their otherwise-uncertain survival.