Seeds

Vigna radiata seeds in greenish shell with whitish markings

Seed coat (testa) - a component of seed seed production. It results from the transformation of the cascade (integumentum), sometimes also from the outer layers of the nucleus (nucellus). Because it is derived from the tissues of the parent plant, the shell contains a double set of (2n) parent chromosomes.

The young shell is made up of thin-walled cells with large vacuoles. As the seeds matured in the shell construction, various changes occur in different plants. Some integrin layers may disappear, cell wall structure and cell contents change. Often, shelled cells are filled with color substances, giving shells characteristic of the individual species of seed color. Often the walls are wooded, so that the husks get hard. Often, however, the cells of the shells are hygroscopic and after wetting they mucus. In some plants, the outer shell cells produce characteristic products - Italian, warts and hooks (eg, cotton fibers are hairs that grow from seed shells).

The hard shell protects the seed against harmful external factors, such as bacterial, fungal, drying, and mechanical damage. In addition to the role of protective shell, it can facilitate spreading, thanks to the formation of additional volatile or clay structures.

There is a trace on the shell, so called. a hila (hilum), which is a remnant of a string and a window through which the root and hippocampus grow. The shell can be planted with fruit, as is the case with grass and cereal seeds.

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