In botany, the seed coat refers to the hard or semi-hard covering that sheathes a seed, protecting it from various types of insects and diseases. Seed coats additionally prevent premature germination by obstructing any excess water from penetrating the seed.
Harder shells also protect the seed from fluctuations in humidity as well as mechanical stress. The function of the seed coat is also to create a barrier between environmental factors and the budding seed.
MaximumYield explains Seed Coat
Seed coats emerge from the plant’s maternal tissue such as the ovule and integuments. In mature seeds such as peanuts, the seed coat can be extremely thin and fragile. On the other hand, coconut, honey locusts, and the likes have a far tougher seed coat. Most botanists differentiate between two main types of seed coat: unitegmic or bitegmic.
While the seed coat is developed from the ovule, it may not be instantly apparent in angiosperms since in these plants, the seed is enclosed within a pericarp or a fruit wall. In corn kernels, for example, the seed coat is actually the visible part that protrudes on the surface. Seed coats usually present two main layers: the tegmen, which is on the delicate side, and the testa, which is thicker and tougher.