Question

A persistent nucellus in the seed is known as?
A) Chalaza
B) Perisperm
C) Hilum
D) Tegmen

Answer 1

Hint: Nucellus is the central cellular mass of the body of the ovule, containing the embryo sac. It forms a layer of nutritive tissue in the seed of a plant. It surrounds the embryo.

Complete answer:
When male gamete fuses with the two polar nuclei in the embryo sac, it results in the formation of a primary endosperm nucleus. The endosperm is the product of the triple fusion and develops from the central cell of the embryo sac. It is triploid tissue. Perisperm is usually a haploid tissue and it is remnant of the nucellus. Being a diploid tissue, it is formed from the nucleus by the equational division and the endosperm is triploid.
i. Chalaza: In plant ovules, the chalaza is located opposite the micropyle opening of the integuments. It is the tissue where the integuments and nucellus are joined.
ii. Perisperm: Perisperm is the nutritive tissue of a seed which is derived from the nucellus and deposited externally to the embryo sac.
iii. Hilum: It is a scar on a seed or spore created by detachment.
iv. Tegmen: It is the delicate inner integument of the seed.
Thus, the correct answer is option B.

Note: An endosperm is meant for providing nourishment to the embryo. It is formed due to the process of double fertilization. In vascular plants, embryo formation, or embryogenesis, usually occurs within a few hours after fertilization. It also contains oil and proteins.