polar nucleus

American  

noun

1. Botany. either of two female haploid nuclei, in the embryo sac of flowers, that fuse to produce a diploid nucleus, which combines with a male nucleus to form the endosperm.

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Etymology

Origin of polar nucleus

First recorded in 1880–85

Example Sentences

In two Malayan species of Balanophora, the embryo is developed from a cell of the endosperm, which is formed from the upper polar nucleus only, the egg apparatus becoming disorganized.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1 by Various

One nucleus from each group, the polar nucleus, passes to the centre of the sac, where the two fuse to form the so-called definitive nucleus.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1 by Various