Question

Monocotyledonous seeds possess a single cotyledon which is represented by
A. Tegmen
B. Endosperm
C. Scutellum
D. Aleurone

Answer 1

Each and every plant grows from a seed. After maturing the plant it produces seeds for the continuity of its generation. These seeds are specific for species and have different shapes, sizes and colours. Broadly they are divided into monocots and dicots depending upon the number of cotyledons present inside them.

Complete answer:
Seeds are essential elements that participate in the sexual reproduction of plants and are the end products of sexual reproduction in gymnosperms and angiosperms. Gymnosperms have naked seeds whereas angiosperms have specialised seed bearing structures called fruits that are produced after the fertilisation. The fruit consists of an embryo which has an embryonal axis, cotyledons and a radicle. Cotyledons are thick swollen structures that have abundant reserve food. A seed has a protective covering known as the seed coat. Seeds can have one or two cotyledons, the one with one cotyledon is known as monocotyledon seeds like that of wheat, garlic, grasses, coconut, and paddy. Seeds having two cotyledons are known as dicotyledons and they include peas, tomato, almonds, and cashews.

-Seed coat is divided into two layers called testa and tegmen. Testa is a thick brownish outer layer and tegmen is inner thin, whitish and it remains attached to the testa. It has an opening at its beak that is known as micropyle.
-Endosperm is a kind of tissue that is responsible for the growth and nourishment of the seeds as it is rich in oils and proteins. Some seeds like that of orchids have no endosperm whereas in coffee seeds endosperm never develops.
-Scutellum is the name given to a single cotyledon found only in monocots like wheat. Scutellum is present at one side of the embryonal axis. At the lower end the embryonal axis has a radicle and root cap which are enclosed in a sheath called coleorhiza. The portion of embryonal axis above the attachment of scutellum is known as epicotyl and it bears shoot apex and it encloses leaf primordial in a hollow foliar structure called coleoptile.
-Aleurone is a protein that is found in protein granules of mature seeds like wheat. It forms an outer layer covering the endosperm lying between pericarp and hyaline layer of endosperm. This layer performs digestive functions by releasing hydrolases that break starch and proteins present in the endosperm during seed germination.

Hence, the correct answer is option (C).

Note: Mature seeds can be albuminous or non-albuminous depending on the availability of the endosperm as it is consumed during seed germination. Albuminous seeds like that of wheat, rice, barley and castor do not use their complete endosperm.