parietal placentation
Học thuậtThân thiện
Definition
Noun (Biology/Botany): A type of placentation in flowering plants where the ovules are attached to the inner wall (the parietal) of a compound ovary, or to outgrowths from that wall. This arrangement often results in the ovary being divided into incomplete or "broken" partitions (locules).
Usage
This is a specific botanical term used to describe the structure of a plant's ovary and the placement of its seeds (ovules) before fertilization. - Parietal placentation is a key characteristic used to classify certain plant families. - In the mustard family (Brassicaceae), the ovary typically exhibits parietal placentation.
Advanced Usage
- Comparative Anatomy: The term is used in comparative studies of plant morphology and taxonomy to differentiate between types of placentation (e.g., axile, free-central, parietal).
- Developmental Biology: It describes the developmental pattern of ovule attachment during the formation of the gynoecium (the female reproductive part of a flower).
Variants and Related Words
- Placentation (n): The general term for the arrangement of ovules within the ovary.
- Parietal (adj): In botany, relating to or situated on the wall of a plant organ or structure.
- Axile Placentation (n): A contrasting type where ovules are attached to a central column in a partitioned ovary.
- Free-central Placentation (n): A type where ovules are attached to a central column that is not connected to the ovary wall by partitions.
Synonyms
- Marginal Placentation: This term is sometimes used synonymously, especially when the ovules are attached along the fused margins of a single carpel, which is a specific form of parietal placentation.
Related Phrases/Concepts
- Compound Ovary: An ovary formed from two or more fused carpels, which is the structural context for parietal placentation.
- Locule: A chamber within the ovary. In parietal placentation, the partitions between locules are often incomplete.
- Replum: A technical term for the thin, persistent partition found in some fruits (like siliques in mustards) resulting from parietal placentation.
Noun
- where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary