Tag: monocot seed

In grain seed, which is moncot and endospermic seed. the embryo consists of an upper shield shaped scutellum which is actually a reduced cotyledon. The scutellum is closely pressed against the endosperm and helps in the translocation of nutrients from endosperm to the growing embryo at the time of germination and seedling growth. So, the correct answer is 'Scutellum'.

Coleoptile is a sheath protecting a young shoot top in monocotyledons such as grasses. They have two vascular bundles, one on either side. 

A. Aleurone layer- In monocotyledonous endospermic seed, endosperm is surrounded by a special one- cell thick layer, called aleurone layer. The cells of aleurone layer are filled with proteinaceous aleurone grains which play an important role at the time of germination.

B. Coleorhiza- Protective sheath of radicle.

C. Scutellum- In monocotyledonous endospermic seed, the embryo consists of an upper shield shaped scutellum wich is actually a reduced cotyledon. The scutellum is closely pressed against the endosperm and helps in the translocation of nutrients from endosperm to the growing embryo at the time of germination and seedling growth.

D. Hilum- It is the point of attachment of the body of the ovule with the funiculus.

In monocots, particularly the grasses where the fruit is a caryopsis, the cotyledon forms a shield like structure the scutellum. Its function is to digest the endosperm and direct the nutrients to the developing embryo. It does not form green leaf like structures as in dicots.

Aleurone layer - a layer of protein storage cells,  present in cereal, maize seed, and is a  form of reserved food material.

In monocots, sieve tube first appears in leaves. The main function of the sieve tube is transport of carbohydrates, primarily sucrose, in the plant (e.g., from the leaves to the fruits and roots). Unlike the water-conducting xylem vessel elements that are dead when mature, sieve elements are living cells. They are unique in lacking a nucleus at maturity.

Apricot, mango, and guava are all dicots (have two cotyledons), while the question asks which group does NOT represent monocots. Monocots include coconut, while dicots include apricot, mango, and guava.

Long filamentous threads protruding at the end of a young cob of maize are styles. The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous and because of its large settling velocity, most pollen falls within a few meters of the tassel. Elongated stigmas, called as silks, emerge from the whorl of husk leaves at the end of the ear. They are often pale yellow and  like tufts of hair in appearance.
At the end of each is a carpel, which may develop into a kernel if fertilized by a pollen grain. The pericarp of the fruit is fused with the seed coat referred to as caryopsis, typical of the grasses and the entire kernel is often referred to as the seed. The cob is close to a multiple fruit in structure, except that the individual fruits never fuse into a single mass. 
Thus, the correct answer is option B.

Seeds of flowering plants are either dicotyledonous or monocotyledonous. While, the dicotyledons are characterized by two kidney shaped cotyledons, these are either non-endospermic exalbumnous or endospermic depending on the presence of endosperm and food storage areas. The monocotyledons with a single cotyledons are also differentiated as endospermic and non-endospermic based on the presence of endosperms. In case of Alisma and orchids, the seeds are extremely small with an undifferentiated embryo that lacks endosperm. They are referred to as acotyledons or exceptional monocots.
Thus, the correct answer is option C.