Tag: biology

Plants are classified into two main groups: the bryophytes (nonvascular plants) and the tracheophytes (vascular plants). The tracheophytes include ferns, gymnosperms and angiosperms, and are characterized by specialized vascular tissues- the phloem and xylem. The study of living species suggests that angiosperms evolved from the gnetophytes, a group of gymnosperms. however, the oldest known angiosperms were a diverse group of plants called magnoliids from which dicots and monocots are evolved. Monocots are more advanced plants than dicot.

The single shield shaped cotyledon of maize is called as scutellum. In maize grain, scutellum is characteristically present, which is a modified cotyledon. The scutellum is part of the structure of a  seedthe modified seed leaf. The scutellum can also refer to the equivalence of a thin cotyledon in monocots. It is very thin with high surface area and serves to absorb nutrients from the endosperm during germination. The scutellum is believed to contain an as yet unidentified protein transporter that facilitates starch movement from the endosperm to the embryo.
Therefore, the correct answer is option D.

A seed in which micropyle and hilum cannot be traced is maize. In maize, 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, the kernels never fuse into a single mass. 

In maize grain, scutellum is characteristically present, which is a modified cotyledon. The scutellum is part of the structure of a  seedthe modified seed leaf. The scutellum can also refer to the equivalence of a thin cotyledon in monocots. It is very thin with high surface area and serves to absorb nutrients from the endosperm during germination. The scutellum is believed to contain an as yet unidentified protein transporter that facilitates starch movement from the endosperm to the embryo.
Therefore, the correct answer is option B.

The phenomenon of an arrangement of veins on the leaf is known as venation. There are two kinds of venation. That is reticulate venation and parallel venation. Reticulate venation contains the irregular distribution of veins to form a network. Examples of plants presenting reticulate venation include rose, tulsi, hibiscus, papaya, Ficus, Bambusa. Parallel venation includes the veins running parallel to each other.

Examples of plants presenting parallel venation include grains, banana, canna, grass, Musa, plum. Leaves of monocot plants show parallel venation. Leaves of dicot plants show reticulate venation. Though, there are exceptions in monocots like Smilax and Colocasia. They show reticulate venation. Other options are not related with reticulate venation.

Thus, the correct option is B.

Scutellum is present in monocotyledons endospermic 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.