Samenhülle

Samenhülle is a German term that translates to "seed coat" in English. It is the protective outer covering of a seed. The seed coat develops from the integuments of the ovule after fertilization. Its primary function is to protect the embryo from mechanical damage, dehydration, and invasion by pathogens. It also plays a role in regulating seed germination by controlling the passage of water and gases into and out of the seed.

The structure of the seed coat can vary significantly among different plant species. It may consist of one or two layers. In some cases, the seed coat can be very hard and thick, providing robust protection, while in others it may be thin and papery. The outer layers of the seed coat are often derived from the outer integument, and the inner layers from the inner integument. These layers can differentiate into various tissues, each with specific functions.

In many species, the seed coat is shed or becomes part of the fruit wall during germination. However, in some cases, it remains attached to the seedling for a period. The seed coat's properties can influence how seeds are dispersed and how they interact with their environment. For example, a hard seed coat might require scarification (damage or weakening) to allow germination, often a mechanism to prevent premature sprouting. The color and texture of the seed coat can also be important characteristics for plant identification.