Micropyle
/ˈmaɪkrəˌpaɪl/
Definition
Micropyle refers to a tiny opening in the ovule, and later in the seed coat, where the integuments do not fully close. In flowering plants, it is the passage through which the pollen tube usually enters the ovule for fertilization. After the seed forms, the micropyle often remains as a small pore near the hilum and can allow water uptake during germination.
Function in Plants
- Route for pollen tube entry: In flowering plants, the pollen tube commonly reaches the ovule through the micropyle, which helps guide sperm cells to the egg for fertilization.
- Influence on seed water uptake: After seeds mature, the micropyle can remain a key point where water enters during imbibition, the first stage of germination when dry seeds rehydrate.
- Visible feature in seed anatomy: On some seeds, the micropyle appears as a tiny pore or mark near the hilum, the scar where the seed was attached, which helps in basic seed identification.
- Part of ovule orientation: Its position is used in botany to describe ovule form and orientation, including whether the ovule curves during development, a trait useful in comparative plant morphology.
Related Terms
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…
Megaspore
Megaspore refers to the larger of the two spore types produced by heterosporous plants and seed plants. It forms inside…
Pollen
Pollen is a fine, powdery substance made in the anthers of seed plants. It consists of tiny grains that carry the male…
Zygote
Zygote refers to the single diploid cell formed when two haploid sex cells fuse during fertilization in plants. In…
Hilum
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…