Question

What is meant by polyembryony?

Answer 1

Hint: Poly means more than one. An early stage of development of a multicellular organism is known as an embryo. So the name Polyembryony and it occurs in humans, animals and as well as plants.

Complete Answer:
Before understanding the term polyembryony, let us discuss briefly fertilisation of the egg in plants and animals.
In a plant, the male sperm cell fuses with ovule to develop seeds. The developed seed consists of the embryo. It may contain more than one embryo also. Similarly, in animals fertilisation may occur either externally or internally. Fusion happens between male gametes and female eggs to form the nucleus of the embryo.
When a single egg is fertilised, there is a possibility for the development of two or more embryos. This special condition is known as Polyembryony, in which one egg produces two offspring that may be genetically identical. Polyembryony can be seen in plants, animals and humans. This is a very common phenomenon in many plants and animal species. In humans, polyembryony results in the formation of identical twins.

Polyembryony in Plants:
Similarly in plants, when more than one embryo develops from a single seed it is known as polyembryony condition. In plants, this phenomenon is caused due to the origination of embryos outside of the embryonic sac.
Polyembryony can be seen in citrus plants, mango and Jamun trees in which multiple seeds arise from a single zygote.

Note: Monoembryony is the development of one and only one seedling from a seed. When a seed gives two or more seedlings are polyembryonic. Polyembryony plays a very important role in horticulture and plant breeding since it helps to produce genetically likewise seeds.