Placenta
/pləˈsɛntə/
Definition
Placenta refers to the tissue inside a flower’s ovary where one or more ovules are attached. It is a plant structure, not the ovule itself. After fertilization, the ovules can develop into seeds, while the ovary becomes the fruit. The position and arrangement of placenta within the ovary, called placentation, are useful features for identifying and describing flowers and fruits.
Function in Plants
- Seed development support: In flowering plants, placenta is the point where ovules receive water and nutrients through the ovary tissues, supporting their growth before they become seeds.
- Clue to ovary structure: Its position helps describe how the ovary is built. Botanists use placentation patterns, such as axial or parietal arrangement, to compare flowers and distinguish plant groups.
- Influence on fruit form: The arrangement of placenta can affect how seeds are spaced inside a fruit and how the internal chambers, called locules, are organized.
- Useful in plant identification: Flower dissections often examine placenta because its placement is a stable reproductive feature that can help identify a species or confirm a family relationship.
Related Terms
Placentation
Placentation describes the arrangement of ovules inside a flower’s ovary and the way they are attached to the placenta…
Ovary
Ovary refers to the enlarged basal part of a flower’s pistil, or female reproductive structure, that contains one or…
Ovule
Ovule is the seed-producing structure inside a flower’s ovary, or on the scales of cones in gymnosperms. It contains…
Pistil
Pistil refers to the female reproductive structure of a flower. It consists of one carpel or several fused carpels and…
Gynoecium
Gynoecium is the female reproductive structure of a flower. It consists of one or more carpels, which may be separate…