Question

Perisperm is
A) Outer part of embryo sac
B) Degenerate synergid
C) Degenerate secondary nucleus
D) Remains of nucleus

Answer 1

Hint: Embryo sacs are haploid, egg-producing structures that constitute the female gametophyte. It can be seen as an oval structure inside the ovule and contains the egg.

Complete answer:
Let’s discuss the given options and find the correct answer:

Option A: Integument forms the outer layer of the embryo sac. It is the protective layer of the ovule. iT develops into a seed coat after the ovule matures after fertilization. Therefore, this is an incorrect option.

Option B: When there is no-hit fertilization, synergid cells are determined to die in either of two ways. Once receiving plant part discharge, one synergid cell degenerates and it is termed the degenerated synergid cell. On receiving pollen tube discharge, one synergid cell degenerates and is termed the degenerated synergid cell. Therefore, this is an incorrect option.

Option C: The secondary nucleus formed by the fusion of two polar nuclei is also called a definitive nucleus. The primary endosperm nucleus is formed by the fusion of male gametes with a diploid secondary nucleus. Therefore, this is an incorrect option.

Option D: Perisperm is the nutritive tissue surrounding the embryo in certain seeds and developing from the nucellus of the ovule. After double fertilization, the remnants of the nucleus of the ovule in the mature seed is called perisperm. The nucleus is the innermost part of the ovule. Perisperm is the remains of the nucleus in seeds. After fertilization, the nucleus develops into the perisperm. It provides nutrition to the developing embryo. It is formed at the micropylar end. It appears as a reddish papery structure. Therefore, this is the correct option.

Thus, the correct answer is option (D) Remains of nucleus.

Note: Do not confuse perisperm for endosperm as these two terms are different. Perisperm is a diploid tissue which arises from the nucleus and endosperm is a triploid tissue which is a result of triple fusion.