A seed is an independent reproductive organ that plays a key role in the development of flowering plants. Inside the seed is the embryo, and around it there is a reserve substance that forms the temporary food of the embryo. Each seed is covered with a shell. The outer shell part of the seed can be of different hardness and color, and the surface can be bumpy, wrinkled, smooth, bumpy, prickly, hairy.
Structure of the seed
Flowering plants are called angiosperms. The reason for this is that the seed is formed in a closed ovary in the main plant as a result of pollination and fertilization and spends its first development in the ovary on the main plant.
The seeds vary greatly in size and weight, as well as whether they are monocots or dicots. They come in a variety of colors and shapes. The kernel in the seed is covered with a shell on the outside. The shell protects the seed from external influences and ensures its integrity. A seed consists of the following parts: cotyledon, kernel (or kernels), pistil, seed coat (skin), endosperm, shoot (leaf). The rhizome, stem and shoot together are called the germ of the seed. In the cotyledons of the seed, the reserve nutrients required for the development of the embryo are located either in the cotyledons, in the embryo itself, or in the endosperm. In the seed of monocotyledonous plants, the embryo has one kernel and nutrients are found only in the endosperm.
Seed composition
The seed contains various substances. The seeds collected from the field, garden and melon seem dry at first glance. But no matter how dry they are, they still contain water.
Organic substances – protein, fat and starch – are contained in the seeds of all plants. However, their amount is different in the seeds of plants.
Cereal plants – wheat, barley, sorghum, corn and other seeds contain starch, and the seeds of dicotyledonous plants – beans, peas, lentils and others – contain a lot of protein.
The seeds of sunflower, hemp, flax, cotton, olive, walnut, hazelnut and many other plants are rich in oil. People cultivate many plants to obtain the organic minerals and oils found in their seeds.
Seed respiration
Just as all living things, plants, animals and humans respire, so do seeds. Humans and animals breathe with special respiratory organs. However, plants do not have special respiratory organs. Just as plants breathe with all their organs, seeds also breathe in this way, absorbing oxygen and releasing carbon dioxide. When the seeds germinate, the embryo respires through the rhizome, stem and leaves. In dry seeds, the respiration process is poor. Their respiration becomes stronger during germination.
