megasporangium
Học thuậtThân thiện
Definition
Noun: A structure within certain plants, specifically vascular plants like ferns and seed plants, that produces and contains megaspores. Megaspores are the larger type of spore that develops into a female gametophyte.
Usage
The term is used in botanical and biological contexts to describe a specific reproductive organ. - The megasporangium is a key structure in the life cycle of heterosporous plants. - In seed plants, the megasporangium is enclosed within the ovule.
Examples
- In ferns, the megasporangium is typically found on the underside of specialized leaves.
- The development of the embryo sac occurs within the megasporangium.
- Botanists studied the megasporangium to understand the evolution of seed plants.
Advanced Usage
- Nucellus: In seed plants, the central part of the ovule that contains the megasporangium tissue is called the nucellus.
- Integument: The protective layers that surround the megasporangium in an ovule.
Variants and Related Words
- Megaspore (noun): The larger spore produced by a megasporangium, which gives rise to the female gametophyte.
- Microsporangium (noun): The contrasting structure that produces microspores (male spores).
- Sporangium (noun): The general term for any spore-producing structure.
Synonyms
- Macrosporangium (noun): A less common synonym for megasporangium.
Notes on Meaning
This term has a single, precise meaning in botany. It refers exclusively to the sporangium (spore-producing structure) associated with female spore (megaspore) production in heterosporous plants.
Noun
- a plant structure that produces megaspores