Integument
/ɪnˈtɛɡjəmənt/
Definition
Integument refers to one or two protective layers of tissue that surround a plant ovule, the structure that contains the egg cell. These layers leave a small opening called the micropyle, where the pollen tube enters during fertilization. After fertilization, the integument usually develops into the seed coat, helping protect the embryo and stored food inside the seed.
Function in Plants
- Seed coat origin: After fertilization, integument develops into the seed coat in most flowering plants. That outer covering helps protect the embryo and stored food as the seed matures and dries.
- Control of pollen entry: A small opening in the integument, called the micropyle, guides the pollen tube into the ovule. Later, the same opening often affects how water enters the seed during germination.
- Taxonomic value: The number and arrangement of integument layers differ among major plant groups. Those patterns help botanists compare lineages and study how seed plants evolved.
- Influence on dormancy: In some species, features derived from the integument contribute to a hard or water-resistant seed coat. This can delay germination until moisture, temperature, or natural wear make conditions more suitable.
Related Terms
Ovule
Ovule is the seed-producing structure inside a flower’s ovary, or on the scales of cones in gymnosperms. It contains…
Micropyle
Micropyle refers to a tiny opening in the ovule, and later in the seed coat, where the integuments do not fully close…
Megasporangium
Megasporangium is a plant structure in which megaspores are produced by meiosis. In seed plants, the megasporangium is…
Seed
Seed is a plant structure formed after fertilization that contains a young plant embryo, stored food, and a protective…