Biology · Sexual Reproduction in Flowering Plants · NEET
No. Endosperm is the food tissue formed after double fertilisation (from the fusion of a male gamete with the two polar nuclei), so it is triploid (3n). Perisperm is the leftover, unused part of the nucellus, so it is diploid (2n) sporophytic tissue and is NOT a product of fertilisation. In most seeds the nucellus is fully used up, but in a few (black pepper, beet) some of it stays behind as perisperm.
In cereal (monocot) grains such as maize and wheat, the endosperm is bulky and stores starch. Its outermost layer is one (or a few) rows of cells rich in protein — this is the aleurone layer. NCERT states the outer covering of the endosperm separates the embryo by a protein-rich (proteinous) layer called the aleurone layer. So it is the protein-rich boundary of the endosperm.
The aleurone layer is the outermost part of the ENDOSPERM, not the seed coat. Because endosperm is triploid (3n), aleurone cells are also 3n. Students often confuse it with the seed coat (which comes from the integuments and is 2n) — but the aleurone layer sits just inside, on top of the starchy endosperm.
Perisperm (persistent nucellus): black pepper and beet are the two NCERT examples. Aleurone layer (protein-rich endosperm boundary): cereal grains like maize and wheat. Perisperm is about the nucellus surviving; the aleurone layer is about a special protein-rich layer of the endosperm — two different structures, so do not mix the examples.
Perisperm and the aleurone layer are frequent one-mark 'terminology' questions. NEET has directly asked 'Persistent nucellus in the seed is known as' (perisperm, 2019) and 'the protein-rich layer separating endosperm from embryo' (aleurone layer, 2025). These are pure recall marks — easy to get if you fix the definitions and the standard examples.
Persistent nucellus in the seed is known as
In the seeds of cereals, the outer covering of endosperm separates the embryo by a protein-rich layer called :
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Perisperm is diploid (2n) because it is leftover nucellus, a sporophytic tissue. It is not a product of double fertilisation.
The aleurone layer is triploid (3n) because it is the outermost part of the endosperm, and the endosperm is triploid (formed from one male gamete plus two polar nuclei).
Black pepper and beet are the standard NCERT examples of seeds where the nucellus persists as perisperm.
It is a protein-rich layer around the starchy endosperm of cereal grains. In germination it releases enzymes (like amylases) that digest the stored starch, though NCERT mainly describes it as the protein-rich layer separating the endosperm from the embryo.
No. In most seeds the nucellus is completely used up during embryo sac and seed development. Perisperm is present only in a few seeds such as black pepper and beet.
