Chalaza is the basal part of the ovule in plants, where nucellus and integuments join. It is present opposite to the micropylar end of an ovule.

Nutrients from plants are transported to nucellus through chalaza. The chalazal end of cells in the embryo sac develops into three antipodal cells.

Ovule or Megasporangium

An ovule or megasporangium contains a female gametophyte or embryo sac in flowering plants. Chalazas is the basal part of the ovule. The inner mass of cells is known as nucellus. It is enclosed by 2-3 layers of integuments. Integuments and nucellus join at the chalaza.


It refers to the process of fertilisation, wherein the pollen tube enters the embryo sac through chalaza. E.g. Casuarina.

Chalaza is also a structure present in the egg of birds. It holds yolk at the centre of egg white.

This was all about Chalaza. Explore notes on other important concepts related to NEET, only at BYJU’S.

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