Meaning of-

Double fertilisation

Polar nuclei

Synergids

Antipodal cells

1. The process in which the two sperm nuclei of a pollen grain unite with nuclei of the embryo sac of an angiosperm plant. One sperm nucleus unites with the egg to form the diploid zygote, from which the embryo develops. The other sperm unites with the two nuclei located in a single cell at the center of the embryo sac. Together these nuclei form the triploid nucleus of the cell from which the endosperm develops. Double fertilization in this form is unique to the angiosperms.
2. The two haploid nuclei found in the centre of the embryo sac after division of the megaspore. They may fuse to form a diploid definitive nucleus before fusing with the male gamete to form the triploid primary endosperm nucleus.
3. One of two small, short-lived nuclei lying near the egg in the mature embryo sac of a flowering plant. The synergids are part of the egg apparatus and are thought to help the pollen nucleus reach the egg cell for fertilization.
4. antipodal cells The three haploid cells in the mature embryo sac of flowering plants that are situated at the opposite end to the micropyle. *Definition of embryo sac The female gametophyte of a seed plant consisting of a thin-walled sac within the nucellus that contains the egg nucleus and other nuclei which give rise to endosperm on fertilization