What is inside the ovule?

Inside a plant ovule you mainly find the embryo sac (female gametophyte) containing the egg cell, two synergids, three antipodals, and a central cell with two polar nuclei, all surrounded by the nucellus and protective integuments leaving a tiny opening called the micropyle.

The ovule is a small, complex structure inside the ovary of a flower that later develops into a seed after fertilization. It is attached to the ovary wall by a stalk called the funiculus. The body of the ovule is wrapped by one or two layers called integuments, which leave a minute pore at one end—the micropyle. Pollen tubes enter through this micropyle to deliver male gametes for fertilization. Under the integuments lies the nucellus, a nutritive tissue that supports the developing embryo sac.

The heart of the ovule is the embryo sac, also called the female gametophyte. In most flowering plants (the common “Polygonum type”), the mature embryo sac contains seven cells with eight nuclei:

• Egg apparatus (at the micropyle end): one egg cell and two helper cells called synergids. Synergids guide the pollen tube and help in delivery of male gametes.
• Central cell: a large cell containing two polar nuclei. It will fuse with a second male gamete to form the triploid endosperm (food reserve) during double fertilization.
• Antipodals (at the chalazal end): three small cells that often degenerate later but may play roles in nutrition and signaling.

When fertilization happens, one male gamete fuses with the egg cell to form the zygote (which becomes the embryo), and the other fuses with the central cell to form the endosperm. Meanwhile, the integuments harden into the seed coat, the nucellus may persist as perisperm in some species, and the ovule overall matures into a seed. The area where the funiculus joins the ovule body is the hilum, a scar later seen on the seed.