Seed

Разнообразие семян

Seed Development Cycle

Ovule-Gymno-Angio-en.svg

Ginkgo embryo and gametophyte

Dycotyledon seed diagram-en

Budowa nasienia-dwuliscienne.svg

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A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperms and angiosperms. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the seed coat from the integuments of the ovule.

Structure

Seeds have three main parts: the embryo, the endosperm, and the seed coat. The embryo is the young multicellular organism before it emerges from the seed. The endosperm is a source of stored food, consisting primarily of starches. The seed coat consists of one or more protective layers that encase the seed.

Types of Seeds

Seeds can be classified into two types based on the number of cotyledons present:

• Monocotyledons (monocots) - Seeds with one cotyledon.
• Dicotyledons (dicots) - Seeds with two cotyledons.

Seed Dispersal

Seed dispersal is the movement or transport of seeds away from the parent plant. Plants have evolved various mechanisms for seed dispersal, including:

• Wind dispersal
• Water dispersal
• Animal dispersal
• Explosive dispersal

Germination

Germination is the process by which a seed develops into a new plant. It involves the reactivation of metabolic pathways, leading to the growth of the embryo into a seedling. Factors affecting germination include water, oxygen, temperature, and light.

Importance

Seeds are of immense biological and economic importance. They are a primary source of human and animal nutrition, providing essential nutrients such as proteins, fats, and carbohydrates. Seeds are also crucial for agriculture, horticulture, and forestry.

See also

• Seed bank
• Seed dormancy
• Seed predation
• Seedless fruit
• Seedling