Hilum
/ˈhaɪləm/
Definition
Hilum refers to the scar or mark on a seed where it was attached to the ovary or fruit wall by the funiculus, the small stalk that connects the seed during development. It appears as a spot, line, or oval on the seed coat and helps distinguish seed structures from nearby features such as the micropyle, the tiny opening where water may enter during germination.
Function in Plants
- Seed attachment point: In seeds, hilum marks where the ovule was attached to the parent plant. That connection is part of how water and nutrients reached the developing seed before it matured.
- Clue for seed identification: Its size, shape, color, and position can help distinguish one species or variety from another. Seed descriptions in botany and agriculture often note hilum as a visible identifying feature.
- Relation to water entry: Hilum sits near other seed-coat features involved in water movement, such as the micropyle, a tiny opening in the seed coat. In some species, that area influences how quickly a seed takes up moisture and begins germination.
- Useful in propagation work: When handling larger seeds, hilum can help orient the seed for close inspection and treatment. It is one of the surface markers growers use when scarifying, soaking, or checking seed condition.
Related Terms
Seed
Seed is a plant structure formed after fertilization that contains a young plant embryo, stored food, and a protective…
Ovule
Ovule is the seed-producing structure inside a flower’s ovary, or on the scales of cones in gymnosperms. It contains…
Integument
Integument refers to one or two protective layers of tissue that surround a plant ovule, the structure that contains…
Micropyle
Micropyle refers to a tiny opening in the ovule, and later in the seed coat, where the integuments do not fully close…
Seedling
Seedling refers to a very young plant that has developed from a seed after germination. It is the stage after the…