Question

The wheat grain has an embryo, with one large shield shaped cotyledon, known as:
a) Coleoptile
b) Coleorhiza
c) Epiblast
d) Scutellum

Answer 1

Hint: The zygote is located at the micropylar end of the embryo sac, where the embryo develops. Monocotyledonous and Dicotyledonous embryos are the two forms of embryos. Sunflower, roses, and other dicot embryos have an embryonal axis and two cotyledons. Monocotyledon embryos, for example, have a single cotyledon.

Complete answer:
a) Coleoptile: The epicotyl has a shoot apex and a few leaf primordia in a hollow foliar structure called the coleoptile in monocot embryo.
So, option (a) is incorrect.
b) Coleorhiza: In monocot embryo, the root cap is enclosed in an undifferentiated sheath called coleorhiza.
So, option (c) is incorrect.
c) Epiblast: It is the reduced cotyledon of a monocot embryo.
Option (c) is incorrect.
d) Scutellum: It is the single shield shaped cotyledon of monocots, situated towards one side (lateral) of the embryonal axis.

Hence the correct answer is option (d).

Note:
Embryo development is called embryogeny. The early stages of this process are similar in both monocots and dicots. The zygote develops into a proembryo, which then matures into a globular, heart-shaped embryo. In an embryo, the portion of embryonal axis above the level of cotyledon(s) is the epicotyl, which terminates with a plumule or stem tip. Hypocotyl is the part of the plant below the level of the cotyledon(s), and it ends in the radicle or root tip. A root cap protects the root tip.
In monocot embryo, coleoptile and coleorhiza are present above and below the plumule and root tip, respectively.