Formation of Seeds and Their Dispersal
After the process of fertilization in a plant, the ovary is grown into a fruit and other parts of the flower fall off.
The ovule gets converted to the seed.
The seed contains embryo enclosed in a protective seed coat and has reserve food to keep the embryo nourished.
The seed is the unit of reproduction of a flowering plant. When it is planted in soil, it gets germinated and a new plant is formed.
Seeds are immobile; they cannot move on their own. But yet, the same kind of plant can be seen growing at different places.
This is possible because of the process of seed dispersal.
Let us try to understand what is seed dispersal.
Dispersal is the spreading or distribution of things over a wide area.
We all might’ve seen small parts of dandelion flying across in the wind. These parts are the seeds of the Dandelion plant.
Lets try to understand the need for seed dispersal.
Usually, the seeds drop from the tree/plant on the ground and grow there acquiring water and minerals from soil.
But they have to fight for the sunlight, water, minerals and space. It could prevent them from growing into a healthy plant.
Hence, many plants prefer dispersing their seeds. It prevents competition between the growing seedlings for basic resources.
It also helps plants in invading new habitats and ensure wider distribution of their species.
According to the habitat of the plants and conditions of growth, different plants follow different methods for seed dispersal.
Let us see the different methods of seed dispersal.
The wind is a common agent for dispersal of seeds.
Seeds of plants like drumstick and maple are spread by wind.
These seeds have winged structures, which helps them to move along with wind currents.
The hairy fruit of sunflower and the hairy seed of madar (aak) are also dispersed with the help of wind.
The wind-dispersed seeds are characterized by being lightweight and having hairy structures. Such seeds are also small in size.
Water is another main agent of seed and fruit dispersal.
These seeds or fruits have a floating ability. These usually have the presence of a spongy or fibrous outer coat. E.g. Coconut
Water Lilies, coconut, cattails etc. are few examples of plants that disperse their seeds with the help of water.
Animals can also be the agents for seed dispersal.
Some seeds have spiny surfaces, which can remain attached to the body of animals and dispersed to distant places.
Beggar ticks, Xanthium, Urena etc. are examples of seeds that spread with the help of animals.
Some plants release their seeds by bursting mechanism or with sudden jerks. These seeds are then scattered from the parent plant.
Plants like castor, balsam etc. disperse their seeds with the mode of bursting.
After fertilization, the ovary grows into a fruit and ovule into the seeds. The seed contains the embryo and they are the units of reproduction.
To prevent the competition between the plant and its seedlings for basic resources, the seeds are often dispersed.
Lightweight seeds with wing-like structures are dispersed with the help of wind.
Floating seeds can be dispersed with the help of water and plants with spiny and sticky seeds are spread with the help of animals.
Some seeds are spread by bursting or sudden jerks. This triggers sudden explosion of the pods and seeds are dispersed.