"seed coat"的定义和意义

What is "seed coat"?

The seed coat, also known as the testa, is the protective outer covering of a seed. It serves to safeguard the embryo within the seed from mechanical damage, pathogens, and dehydration. The seed coat varies in thickness, texture, and composition depending on the plant species. In some seeds, the coat may be thin and papery, while in others, it can be thick and hard. The seed coat also plays a role in regulating water and gas exchange during seed germination, helping to create optimal conditions for the embryo to sprout and grow. Additionally, the seed coat may contain chemical compounds that inhibit germination until environmental conditions are suitable for growth.