basal placentation
Học thuậtThân thiện
Definition
Noun: - A type of placentation in plants: Basal placentation is a botanical term describing the arrangement of ovules within an ovary. Specifically, it occurs when one or a small number of ovules are attached at the very base (the bottom) of a simple ovary or of each carpel in a compound ovary.
Usage
- This term is used in botany and plant morphology to classify and describe the structure of flowers and fruits.
- It is a technical descriptor for a specific reproductive feature in flowering plants (angiosperms).
Examples
Advanced Usage
- Evolutionary Significance: Basal placentation is often considered a simple or ancestral form, frequently associated with plants that produce a single seed per flower (like a sunflower "seed," which is technically a fruit called an achene).
- In Compound Ovaries: In a syncarpous (compound) ovary formed from multiple fused carpels, basal placentation can mean a single ovule is positioned at the base of the entire structure, rather than in each locale.
Variants and Related Words
- Placentation (n): The general term for the arrangement of ovules within the ovary. Other types include , , , and placentation.
- Ovule (n): The structure that develops into a seed after fertilization.
- Ovary (n): The part of the pistil (female reproductive organ) that contains the ovules.
Synonyms
- Basifixed placentation: A less common but technically accurate synonym emphasizing the ovule's attachment point.
Related Terms (Contextual)
- Achene: A simple, dry, one-seeded fruit that does not open at maturity, commonly derived from a flower with basal placentation (e.g., sunflower, buttercup).
- Simple Pistil / Carpel: A structure consisting of a single ovary, style, and stigma, which may exhibit basal placentation.
Noun
- where one or few ovules develop at the base of a simple or compound ovary