Polyembryony

Abstract

Angiosperms show the unique phenomenon of double fertilization. The egg, after fertilization, develops into an embryo. It is nourished in the younger stages by the suspensor, and in later stages by the endosperm - a post-fertilization tissue resulting from the fertilization of polar nuclei. Besides the egg, other constituent cells of the embryo sac, with or without fertilization, produce embryos. Moreover, the activity of one or more cells of the ovule, outside the embryo sac, also leads to the development of accessory embryos. Such embryos are asexual. Thus, in addition to the zygotic embryo, sexual and/or asexual non-zygotic embryo(s) may also develop in the same seed. Such a condition is referred to as ``polyembryony''.