Tag: seeds - structure and germination

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.

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.