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**Location and Structure of Ovule**:
Ovule is located inside the gynoecium of flowering plants.
– Ovary of the gynoecium produces ovules that become the fruit wall.
– Ovules attach to the placenta in the ovary via funiculus.
– Different patterns of ovule attachment include apical, axile, basal, free-central, marginal, and parietal placentation.
– In gymnosperms, ovules are borne on ovuliferous scales within an ovulate cone.

**Integuments, Micropyle, and Chalaza**:
– Integuments protect the ovule; gymnosperms have one, angiosperms have two.
– Inner integument may have evolved from enclosing a megasporangium.
– Outer integument’s origin is debated; may have evolved from cupules.
– Integuments develop into the seed coat after fertilization.
– Micropyle allows pollen entry for fertilization; closes afterward.

**Nucellus and Megaspore Development**:
– Nucellus is inside the ovule, containing diploid cells.
– Nucellus is equivalent to the megasporangium.
– Megasporocyte in the nucellus undergoes meiosis.
– Gymnosperms typically have one surviving megaspore in the nucellus.
– Angiosperms show variation in megaspore survival and embryo sac development.

**Types and Evolution of Ovules**:
– Orthotropous ovule has micropyle, chalaza, and funicle in a line.
– Other types include anatropous, hemitropous, campylotropous, amphitropous, and epitropous.
Ovule types vary in the relative positions of micropyle, chalaza, and funicle.
– Examples of orthotropous ovules include Piper, Polygonum, and Cycas.
Ovule types determine the orientation and attachment of the ovule in the ovary.

**Reproductive Process and Development**:
– Ovules in seed plants give rise to female reproductive cells.
Ovule consists of integument, nucellus, and female gametophyte.
– Female gametophyte produces egg cell for fertilization.
– After fertilization, ovule contains a zygote and embryo.
– In flowering plants, endosperm tissue forms for nourishment of the sporophyte.

Ovule (Wikipedia)

In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the integument, forming its outer layer, the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center. The female gametophyte — specifically termed a megagametophyte— is also called the embryo sac in angiosperms. The megagametophyte produces an egg cell for the purpose of fertilization. The ovule is a small structure present in the ovary. It is attached to the placenta by a stalk called a funicle. The funicle provides nourishment to the ovule.On the basis of the relative position of micropyle, body of the ovule , chalaza and funicle , there are six types of ovules . (a) Orthotropous ovule - the micropyle , chalaza and funicle all lie in the same straight line, this is the most primitive type of ovule . Eg: Piper, polygonum and cycas.

Location of ovules inside a Helleborus foetidus flower
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