Megasporangium (Ovule)
Describes the structure of the ovule, including funicle, hilum, integuments, nucellus, micropyle, and chalaza.
What is Megasporangium (Ovule)?
A plant structure that produces megaspores, typically developing into a female gametophyte; in angiosperms, it is the ovule.
Key points
- Identify and describe the different parts of an ovule.
- Explain the function of each part of the ovule.
- Understand the relationship between the ovule and seed formation.
- Differentiate between micropyle and chalaza.
Common exam trap
Confusing ovule with ovary.
Definitions
- Term
Megasporangium
- Meaning
A plant structure that produces megaspores, typically developing into a female gametophyte; in angiosperms, it is the ovule.
- Term
Ovule
- Meaning
The structure within the ovary of a flowering plant that contains the female gametophyte and develops into a seed after fertilization.
- Term
Funicle
- Meaning
The stalk that attaches the ovule to the placenta.
- Term
Hilum
- Meaning
The scar on a seed marking the former point of attachment to the funicle.
- Term
Nucellus
- Meaning
The nutritive tissue forming the main body of the ovule, derived from the parent sporophyte.
- Term
Integuments
- Meaning
Protective outer layers of the ovule, which develop into the seed coat.
- Term
Micropyle
- Meaning
A small opening in the integuments of an ovule through which the pollen tube usually enters.
- Term
Chalaza
- Meaning
The basal part of the ovule, opposite the micropyle, where the integuments and nucellus join.
Learning objectives
Identify and describe the different parts of an ovule.
Explain the function of each part of the ovule.
Understand the relationship between the ovule and seed formation.
Differentiate between micropyle and chalaza.
Prerequisites
Basic plant anatomy (stamen, pistil, ovary).
Understanding of sporophytic and gametophytic generations.
Concept of fertilization.
Common mistakes
Confusing ovule with ovary.
Incorrectly identifying the functions of nucellus, integuments, micropyle, and chalaza.
Not understanding the developmental relationship between megaspore and embryo sac within the ovule.
Keywords
Ovule
Megasporangium
Funicle
Hilum
Nucellus
Integuments
Micropyle
Chalaza
Embryo sac
Seed development
Angiosperms
Practice preview
What is the stalk that attaches the ovule to the placenta called?…
easy
Which part of the ovule provides protection to the nucellus and the developing embryo sac?…
easy
The basal part of the ovule, diametrically opposite to the micropylar end, is known as the:…
easy