Question

The structure coleorhiza in a maize grain, is the covering of-
a. Radicle
b. Plumule
c. Scutellum
d. Aleurone layer

Answer 1

A portion of the seed-bearing plant embryo that grows into the main root. It is the first component of a seedling (a developing plant embryo) to develop during the germination process from the seed.

Complete answer:

Option A is correct. Coleorhiza is a sheath-like structure which binds the coleoptile to the main root of the plant in a plant seed and serves as a protective covering that encloses the plumule and radicle. The coleorhiza structure in a maize grain is the covering of the radicle. In germination, it is pierced by the root.

Option B is incorrect. A young shoot also known as plumule, is negatively geotropic because it moves away from the soil; it rises above the cotyledon stage by the extension of either the hypocotyl, the area between the radicle and the cotyledon, or the epicotyl, the segment.

Option C is incorrect. The Scutellum, the modified seed leaf, is part of a barley and rice seed structure. In monocots, the scutellum may also refer to the equivalence of a thin cotyledon. It is very thin with a high surface area and, during germination, helps to absorb endosperm nutrients.

Option D is incorrect. The outermost layer of the endosperm is the aleurone layer, preceded by the inner starchy endosperm. Often, this layer of cells is referred to as the peripheral endosperm. Aleurone performs an essential digestive role during germination, secreting hydrolases to break down the starch and proteins contained in the cells of the starchy endosperm.

Hence, the correct answer is option (A).

Note: The radicle often develops toward the ground downwards. It doesn't matter how the seed is positioned; it will turn around as it grows so that it always points downward if the radicle is pointed upwards as it comes out of the seed.