Question

The single shield-shaped cotyledon of maize is called as
A. Tigellum
B. Obturator
C. Coleoptile
D. Scutellum

Answer 1

Hint: The cotyledon is a seed leaf present inside a seed embryo. Flowering plants are grouped as monocots or monocotyledonous plants whose embryos have a single cotyledon; embryos with two cotyledons are grouped as dicotyledonous or dicotyledonous plants. It is a modified seed leaf in maize and barley.

Complete answer: The changed seed leaf is a part of the barley and rice seed structure. In monocots, the scutellum may also correspond to the equivalence of a thinner cotyledon. It is very small with a high surface area and, during germination, it helps to absorb endosperm nutrients. The single shield-shaped cotyledon of maize is called scutellum.
a) Tigellum: It is the embryo’s main axis or stalks which lie between the root and the plumules. One end of the cotyledon tigellum bulges and lies next to the micropyle and is known as the radicle. The other end of the tigellum is the feathery plumule.
b) Obturator: It is present near the micropyle of each ovule in the ovary of some plants. It is an outgrowth of the placenta, central to the micropyle in nourishing and directing pollen tubes. Some fruit types' ovaries are dehiscent; the ovary wall is divided into parts called valves.
c) Coleoptile: It is the pointed protective sheath that covers the emerging shoot in monocotyledons such as grasses in which few monocot embryo leaf primordia and shoots apex remains enclosed. Coleoptiles, one on each side, have two vascular bundles.
Hence, the correct answer is option D.

Note: Scutellum is called the single shield-shaped maize cotyledon. Scutellum, which is a modified cotyledon, is characteristically found in maize grain. The scutellum forms part of the seed arrangement of a transformed seed leaf. In monocots, the scutellum also may refer to the similarity of a thin cotyledon. It is suspected that the scutellum contains an unidentified protein transporter which facilitates the movement of starch from the endosperm to the embryo.