Tegmen

Definition

The tegmen is the inner protective layer of a seed coat in flowering plants. It surrounds the embryo and works in conjunction with the outer layer, known as the testa.

5 Must Know Facts For Your Next Test

1. The tegmen is derived from the nucellus tissue in ovules.
2. It plays a crucial role in protecting the developing embryo from physical damage and pathogens.
3. During seed maturation, both the tegmen and testa undergo physiological changes to enhance seed viability.
4. In some seeds, the tegmen can be thin and membranous or thick and lignified depending on species-specific adaptations.
5. The interaction between tegmen and testa contributes to seed dormancy mechanisms by controlling water uptake.

Review Questions

• What is the primary function of the tegmen in a seed?
• How does the structure of the tegmen vary across different plant species?
• Explain how the tegmen contributes to seed dormancy.

Related terms

testa:

The outer layer of a seed coat that works with the tegmen to protect the seed.

nucellus: Tissue within an ovule that gives rise to both integuments forming seed coats like testa and tegmen.

embryo: The young multicellular organism before it emerges from the seed, surrounded by protective layers like testa and tegmen.