A flowering plant’s seed is an essential component of the plant’s life cycle. They result in the growth of a new plant. They can be found in a variety of shapes, colours, and sizes. They can be round, wrinkled, winged, or hairy depending on the species. They are in a dormant state until such time as they receive adequate sunlight, water, and soil to grow again. Germination is the term used to describe the process by which a plant grows from a seed. A seed is composed of three parts: the Seed Coat, the Endosperm, and the Embryo.
The seed of a plant is the part of the plant that develops from the ovules after it has been fertilised. They are contained within the fruit, which develops from the fertilised ovary after fertilisation. The seeds are produced as a result of sexual reproduction and contain a young embryo that has the potential to develop into a new plant species.
Seed Coat
The internal parts of a seed are protected by the seed coat. There are two layers to the seed coat. The Testa is the thick outer coat that protects the body from the elements. Tegmen is the name given to the thin inner layer of the skin.
A thick seed coat protects the seed from exposure to sunlight and water, and it also helps to retain moisture. It prevents the loss of water and the introduction of parasites into the seeds throughout the growing process. When exposed to unfavourable environmental circumstances, the hard seed coatings prevent germination from occurring.
Known as the micropyle, it is a hole in the integument of the ovule that may be seen on the surface of some seed coats. The hilum, which is the equivalent of the naval in humans and is where the umbilical cord is attached, is also evident in this image.
Endosperm
The endosperm contains the nutrients that have been stored there. Because it contains carbs, carbohydrates, and proteins, it is a good source of nutrients for the seed, which helps it germinate successfully. It can be found just below the seed coat. The seeds will remain viable as long as they are fed with nutrients until they germinate.
The endosperm can be mealy, continuous, or ruminate in consistency. In the case of an endosperm, the chromosomal complement is triploid.
The endosperm of maize and other grains makes up a significant amount of the seed’s weight. In seeds such as beans, the endosperm is consumed in the formation of the embryo and is therefore absent from the seed. The liquid endosperm of the coconut is called copra.
Embryo
The embryo is the most significant portion of a seed since it contains the most information. It is a diploid organism that develops from a fertilised egg. The embryo contains all of the cells that are required for the development of a fully developed embryo. An embryo is made up of the following components:
- Epicotyl
- Hypocotyl
- Radicle
- Cotyledons
The epicotyl is a small shoot that is responsible for the development of the entire plant’s shoot system.
During germination, the primary root is the first to emerge. It is also referred to as hypocritical. It helps to secure the plant’s position in the soil.
A radicle is a small embryonic root that grows from the embryonic stem.
The cotyledons are responsible for providing nourishment to various parts of the embryo. During the growth of the seedling, it emerges from the soil as a tiny or fleshy leaf with the seedling. Food is stored in the form of carbohydrates and protein in the liver.
The embryonic leaves are the first to emerge above the surface of the soil. An embryo is formed when a fertilised egg is laid.
Importance of seed
- The embryo plant is shielded by the seeds, which permits it to develop once it has found suitable soil to grow.
- Seeds serve as a protective structure for plant embryos, allowing them to survive for an extended period of time before germinating.
- The seed can remain latent until the embryo’s developing conditions are favourable, at which point it will sprout.
- Food sources for plant embryos are pre-packaged in seeds in order to meet the nutritional requirements of embryos throughout their early stages of development. Nature, including animals like birds and mammals that move seeds swiftly, enables the plant to colonise large areas of land quickly. Some of them are capable of being carried wherever by the wind.
- Seeds can live in the absence of water, allowing the plant to survive in the event of a drought.
- Seeds are produced in large quantities in order for plants to reproduce successfully.
Conclusion
A seed is a structure that protects the embryo of a plant by surrounding it with a protective outer coat. A seed gives rise to a new plant by utilising the nutrients stored within it when development conditions are ideal for the seed.
It is the union of the male and female reproductive cells that occurs within the mature ovule of a flower that aids in the production of seeds in a plant. Seeds of varied sizes, forms, and colours are used in the reproduction of blooming plants, and each seed has its own characteristics.