The main axis of the embryo in which fleshy cotyledons are attached is called tigellum. The upper end of the tigellum bearing some crowded immature leaves is called plumule and the lower end which give rise to root is the radicle.

The process in which nonmotile male gametes are transported up to the female gamete through a pollen tube is called siphonogamy. In angiosperms, the male gametes are formed inside the pollen grains. After pollination, it germinates and produces a pollen tube. It carries the male gametes into the embryo sac located in the ovule inside the ovary.

The endosperm is a tissue produced inside the seeds of most of the flowering plants after fertilization. The endosperm is generally triploid (3N), produced by the fusion of a diploid polar nucleus with a haploid gamete. It contains starch as a reserve food material apart from that also contains a few oils and lipids. It is surrounded by one cell thick aleurone layer. It surrounds the embryo.