Question

What is the ploidy of endosperm in angiosperms?

Answer 1

The endosperm of angiosperm mostly contains three chromosome sets per nucleus. Endosperm in angiosperms is formed by the process known as double fertilization. The endosperm in angiosperms develops from the secondary nucleus.

Complete answer:
Double fertilization, the name suggests that the fertilization is taking place twice. After pollination, the pollen tube releases two sperm cells. Out of the two, one of the sperm nuclei fertilizes the egg cell, forming a zygote, while the other sperm nuclei usually fuse with the central cell, forming a primary endosperm cell which is triploid.
The primary endosperm nucleus further evolves into an endosperm. Endosperm has reserve food materials and is used to provide nutrition to the embryo. There are three types of endosperm development. They are:
Nuclear endosperm formation - In this repeated free- nuclear divisions take place. This type of endosperm is usually liquid. For example, Coconut water is an example of a nuclear endosperm.
- Cellular endosperm formation - In this, a cell-wall formation is coincident with nuclear divisions. Coconut meat is cellular endosperm.
- Helobial endosperm formation – In this type, a cell wall is found between the first two nuclei, so because of which one half develops endosperm along with the cellular pattern, and the other half along with the nuclear pattern i.e endosperm is divided with both the patterns.

Note: The ploidy of endosperm is different in angiosperm and gymnosperm. In gymnosperm, the ploidy of the endosperm is haploid. The endosperm of a gymnosperm is a pre-fertilization tissue which means it is similar to the female gametophyte. Double fertilization is absent in the case of Gymnosperms.