Question

The undifferentiated sheath that encloses the radicle and root cap in a monocot embryo, is known as :

• A. Coleoptile
• B. Coleorrhiza
• C. Epiblast
• D. Scutellum

Hint:

Coleoptile covers the shoot. The sheath that covers the radicle and root cap is the coleorrhiza.

Answer 1

The Correct Option is B

Step 1: Understand the question:
A monocot embryo has one cotyledon and an embryonal axis. The axis has a shoot end (plumule) and a root end (radicle with the root cap).
Each end is covered by a protective sheath. The question asks about the sheath on the root end.

Step 2: Recall the two sheaths:
The plumule is enclosed in a hollow, leaf-like sheath called the coleoptile.
The radicle and the root cap are enclosed in an undifferentiated sheath called the coleorrhiza.

Step 3: Check each option:
(A) Coleoptile covers the shoot tip, not the radicle. So it is wrong.
(B) Coleorrhiza covers the radicle and root cap. So it is correct.
(C) Epiblast is a small scale-like outgrowth seen opposite the scutellum in some grasses. It is not a sheath of the radicle.
(D) Scutellum is the single shield-shaped cotyledon of a grass seed. It passes food from the endosperm to the embryo.

Final Answer:
The sheath over the radicle and root cap is the coleorrhiza, option (B).