The following diagram shows an endospermic seed of Maize grain. Answer the following question:
In diagram the sheath which covers radicle is shown by ?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → D
In the grass family the radicle and root cap are covered by a sheath, the coleorhiza. In the figure it is D, at the lower tip of the embryo.
Option (1) A — Incorrect. A is the coleoptile, which covers the plumule.
Option (2) B — Incorrect. B is the shoot apex with leaf primordia.
Option (3) C — Incorrect. C points to the embryonal axis below the shoot, not to a sheath.
Option (4) D — Correct. In the grass embryo, the radicle and root cap are enclosed in an undifferentiated sheath called the coleorhiza. In the figure, the coleorhiza is D.
NCERT Extract:
Embryo – “… Embryos of monocotyledons (Figure 1.14 b) possess only one cotyledon. In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis. At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called coleorrhiza. The portion of the embryonal axis above the level of attachment of scutellum is the epicotyl. Epicotyl has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure, the coleoptile.”
