Biology · Morphology of Flowering Plants · NEET
The aleurone layer is the outermost layer of the endosperm in cereal (monocot) grains. It is a protein-rich (proteinous) layer. NCERT says the outer covering of the endosperm separates the embryo by a proteinous layer called the aleurone layer. So it belongs to the endosperm side and forms a boundary between the food-storing endosperm and the embryo. For NEET, remember it is protein-rich, not starchy (the inner endosperm stores starch).
The scutellum is the single, large, shield-shaped cotyledon of a monocot seed such as maize. Its job is to absorb food from the endosperm and pass it to the growing embryo. NEET often asks 'Cotyledon of maize grain is called?' and the answer is scutellum. Do not confuse it with coleoptile or coleorhiza, which are protective sheaths, not the cotyledon.
The scutellum is the cotyledon (the food-absorbing leaf part) of a monocot embryo. The coleoptile is a protective sheath that covers the plumule (young shoot). So scutellum = food organ, coleoptile = shoot cover. Similarly, the coleorhiza is the sheath that covers the radicle (young root). Keep these three separate: one cotyledon, two protective sheaths.
The epiblast is a small, rudimentary second cotyledon found on the opposite side of the scutellum in some monocot embryos (like grasses). It is tiny and does not develop fully. In NEET matching questions, epiblast is matched with 'rudimentary cotyledon'. It is easy to confuse with the scutellum, but the scutellum is large and functional while the epiblast is small and vestigial.
The endosperm is the food-storing tissue formed after double fertilisation (it is triploid). The perisperm is the leftover, persistent part of the nucellus (a maternal, diploid tissue) that stays in the mature seed. So perisperm comes from the nucellus, not from fertilisation. Examples of seeds with perisperm are black pepper and beet. NEET matches perisperm with 'persistent nucellus'.
Maize is an endospermic (albuminous) seed, so it keeps a bulky endosperm, and the outer layer of that endosperm is the protein-rich aleurone layer. The nucellus in maize is used up during development, so no perisperm remains. Perisperm only appears in special seeds like black pepper and beet where the nucellus does not get fully used and persists.
In the seeds of cereals, the outer covering of endosperm separates the embryo by a protein-rich layer called:
Match List I with List II. A. Scutellum; B. Non-albuminous seed; C. Epiblast; D. Perisperm. List II: I. Persistent nucellus; II. Cotyledon of Monocot seed; III. Groundnut; IV. Rudimentary cotyledon. Choose the option with all correct matches.
Cotyledon of maize grain is called:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
The aleurone layer is protein-rich (proteinous). The inner starchy endosperm stores starch, but the aleurone layer itself is a protein-rich boundary layer between the endosperm and the embryo.
Seeds like black pepper and beet show a perisperm. It is the remaining, persistent part of the nucellus that is not used up during seed development.
The scutellum is part of the embryo, so it is diploid (2n). Do not confuse it with the endosperm it absorbs food from, which is triploid (3n).
The scutellum absorbs digested food from the endosperm and transfers it to the growing embryo (plumule and radicle) during germination in monocot seeds like maize and wheat.
No. The perisperm is leftover nucellus tissue (diploid, maternal), while the endosperm is formed after double fertilisation (triploid). They are different tissues with different origins.
