Seed Dispersal

The seed develops after fertilization and after fertilization ovules are converted into fruit and the ovary converts into seeds. The main purpose of all the seeds is reproduction. There are mainly two types of seeds: monocotyledon seeds and dicotyledon seeds. For seed growth, we need to disperse the seed to the desirable places which are suitable for their growth.

Seed dispersal is the mechanism where seeds are transported from plants to their germination site for the generation of new individuals. There are different forms and agents of seed dispersal present in the surroundings like gravity, wind, ballistics, water, insects, and animals. Plants have very limited mobility and rely upon various dispersal vectors to transport their seeds. Seeds can be dispersed away from the main or parent plants singly or wholly and dispersed in both space and time.

Seeds

Seeds have been a very important development in reproduction, which results in the success of gymnosperm and angiosperm plants on the earth, relative to plants that are primitive such as ferns, mosses, and liverworts, which cannot produce seeds, they depend on water for their propagation. Seed plants now become dominant in biological places like on land, from forests to grasslands both in hot and cold climates. In flowering plants, the ovary ripens to a fruit that contains the seed. Seeds are also known as a unit of reproduction in flowering plants. Seeds are capable of developing into other such plants.

Types of seeds

Mainly seeds are divided into two types.

The two types of seeds are,

• Monocotyledonous seeds

In monocotyledon seeds, there is only one cotyledon present, for example, corn wheat, rice, etc. Based on stored food monocotyledon seeds are divided further into Monocotyledonous Albuminous seeds, for example, Maize, wheat, bamboo, etc, and Monocotyledonous exalbuminous seeds for example Vallisneria.

• Dicotyledonous seeds

In dicotyledon seeds, two cotyledons are present, for example, mango, peas, almonds, etc. based on stored food dicotyledon seeds are divided further into Dicotyledonous albuminous. Seeds, for example; the poppy and custard apple and Dicotyledonous non- endospermic Seeds for example; mango and mustard.

Seed dispersal 

Seed dispersal is the mechanism seeds of plants are transported from plants to their site of germination for the generation of new individuals. Seeds dispersal is a passive process that does not require any energy because seeds are dispersed by agents.

Taller plants disperse seeds at larger distances as compared to small plants.

Significance of seed dispersal 

• Seed dispersal helps the plant in their survival because if the plants from the same species grow together, then they have to compete for light, water, and minerals that they are getting from the soil.
• Seed dispersal allows plants to spread and grow in a large area.
• With the help of seed dispersal plants may acquire new habitat, which is more suitable for the growth and development of their species. Overall seed dispersal helps in the survival of plants in the surrounding area.
• Seeds dispersal is a very important procedure in the movement of plant genes.
• Seeds dispersal also helps plants from mortality near their parent plant due to predation by animals, diseases.

Agents of dispersal of seeds

There are some biotic and abiotic agents of seed dispersal present in our surroundings.

Abiotic agents of seed dispersal 

Abiotic agents of seed dispersal involve wind and water.

Seed dispersal by wind

Seeds from plants are light and have feathery bristles and are carried at long distances by the wind. They do not float in water but flutter to the ground. Seeds that are dispersed by the wind develop special structures, which enable seeds to carry away at long distances. These structures involve hair-like and wing-like outgrowths, which support the seeds to get carried away.

Some examples are seed dispersal by wind dandelions, swan plants, orchid plants, cottonwood trees, hornbeam, ash, and cattail.

Seed dispersal by water

Many seeds from plants use water as a medium of dispersal. Seeds float away in water from the parent or main plants. Seeds that use water as means of dispersal have a  hard seed coat that allows them to float protectively in streams and rivers. They have light and buoyancy. The seeds that are dispersed by water live near water.

Some of the examples of seed dispersal by water coconut, lotus, etc.

Biotic agents of seeds dispersal 

Biotic agents of seed dispersal involve animals and insects.

Seed dispersal by Animals

Seed dispersal is done by animals because sometimes they are unable to digest the seeds, and they dispersed these undigested seeds to various places along with their waste. Some seeds have hooks they attach themselves to the fur of animals and get dispersed to various places. Human beings also play an important role in the dispersal of seeds by moving to new places and discarding the inedible portions containing the seeds. Some examples of seeds dispersed by animals are dates, sea grapes, tomatoes, raspberries, etc.

Seed dispersal by insects 

Insects disperse seeds to underground nests, where they may germinate. Some insects which help in the dispersal of seeds are Wasps, Scarabaeoids, etc, and seeds that are dispersed by insects are Myrmecochorous seeds, etc.

Conclusion 

Seeds are a very important part of reproduction and seed dispersal is an important procedure of the environment. We all know that different types of forests, grasslands are formed because of seed dispersal, which is carried by abiotic and biotic agents of seed dispersal. There is a lot of major significance of seed dispersal present in our surroundings. Seed dispersal helps in the modification of genes which helps the plants to grow in their adequate surroundings. It also protects the plant from many predators.