Question

Residual persistent nucellus is known as
A. Perisperm
B. Integument
C. Pericarp
D. None of the above

Answer 1

Nucellus is the inner part of an ovule that encloses the female gametophyte. It is present around the centre nuclei.

Complete answer:
Perisperm is the mass of nutritive material around the embryo sac. They get deposited external to the embryo sac – distinguished from endosperm. Eg. black pepper. That’s why ‘option A’ is correct.
Integument is a tough, protective layer of cells surrounding the ovule. Gymnosperms have one integument whereas angiosperms have two integuments. When the ovary matures after fertilisation, the integument develops into the seed coat. That’s why ‘option B’ is incorrect.
Pericarp is the wall of a fleshy fruit, typically edible. It develops from the ovary wall of the flower and protects the seed by surrounding it. Generally, it consists of three layers, the epicarp, mesocarp, and endocarp. That’s why ‘option C’ is incorrect.

Hence, the correct answer is option (A).

Additional information:
Perisperm develops from the nucellus of the seed by mitosis, and thus it is diploid. It is very much different from endosperm. Endosperms are generally triplod in nature. It is generally formed when male gamete fuses with the two polar nuclei in the embryo sac. They both provide nourishment to the embryo. Perisperm is usually dry whereas endosperm is usually in fluid form. When both perisperm and endosperm are present in seeds, they are known as albuminous, whereas if neither of them are present then they are known as exalbuminous.

Note: Perisperm originates from the nucleus. They are diploid in nature. They are purely maternal. They are found in several families like Chenopodiaceae, Cannaceae, Caryophyllaceae, etc. Examples include sugar beet, coffee and black pepper.