Question

A grain of maize is the –
A. Embryo
B. Seed
C. Fruit
D. Fruit and seed

Answer 1

Hint:Maize is a monocotyledonous plant. The fruit of a monocot plant is called a caryopsis. The fruit wall and seed wall are fused in monocots.

Complete answer: The maize grain is a fruit and a seed. A seed is formed by the maturation and ripening of the ovule. The fruit is formed by the maturation and ripening of the ovary. In a maize grain, the wall of the ripened ovule and the wall of the ripened ovary are fused together.
The maize grain is a typical example of monocotyledon seed. In maize grain, the seed coat ( also known as testa) is fused with the fruit wall ( also known as pericarp). Externally, the maize grain is yellow in color and triangular in shape. On one side of the grain, there is a small, opaque, oval, and whitish area in which the embryo is embedded.

So, the answer is option D.

Additional information:
A longitudinal section of the seed has the following structures:
Seed coat: It is a thin layer surrounding the whole grain. This layer is made up of the ovule wall and the ovary wall fused together.
Endosperm: The seed consists of two unequal portions divided by a layer called the epithelium. The bigger portion is the endosperm which is yellowish or whitish. It is the food storage tissue of the grain and is rich in starch. Its outermost layer contains only protein and is called the aleurone layer. On the other side of the endosperm, towards the pointed end, lies an opaque body called the embryo.
Embryo: It consists of one large shield-shaped cotyledon. It is also known as scutellum in maize and other cereals. The axis of the embryo is embedded in the scutellum. The axis consists of a plumule at the upper portion and a radicle at the lower end.

Note: The maize grain is a fruit and a seed. There is no thickening of the ovary wall to form fruit. Seed coat and fruit coat are fused and both are scaly.