Tohum

Tohum is the Turkish word for seed, the reproductive unit of many plants. In biology, a seed is formed after fertilization of ovules in seed plants, and it typically contains an embryo, a nutrient reserve, and a protective seed coat. Seeds enable plants to survive unfavorable conditions and to disperse offspring away from the parent. They differ from spores in size, structure, and the way they store nutrients, but both serve to propagate the species.

In angiosperms, seeds usually consist of embryo, endosperm, and testa; monocot seeds have a single cotyledon while dicot seeds typically have two. The endosperm provides stored nutrients; the seed coat protects the embryo during dormancy and dispersal.

Germination and dormancy: Upon exposure to favorable conditions, seeds resume growth: water uptake (imbibition) triggers metabolism; the embryo expands and the radicle emerges. Dormancy mechanisms prevent germination until conditions are right and can be broken by stratification, scarification, light, or temperature cues.

Ecological and economic importance: Seeds support plant reproduction and hold major ecological roles; humans depend on seeds for food crops, forestry, and horticulture. Seed quality, vigor, and genetic diversity are central to agriculture; seed banks preserve genetic diversity.