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Question
With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
Solution
An ovule is a female megasporangium where the formation of megaspores takes place.
The various parts of an ovule are:
- Funiculus: It is a stalk-like structure which represents the point of attachment of the ovule to the placenta of the ovary.
- Hilum: It is the point where the body of the ovule is attached to the funiculus.
- Integuments: They are the outer layers surrounding the ovule that provide protection to the developing embryo.
- Micropyle: It is a narrow pore formed by the projection of integuments. It marks the point where the pollen tube enters the ovule at the time of fertilisation.
- Nucellus: It is a mass of the parenchymatous tissue surrounded by the integuments from the outside. The nucellus provides nutrition to the developing embryo. The embryo sac is located inside the nucellus.
- Chalazal: It is the basal, swollen part of the nucellus from where the integuments originate.
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