Question

Plumule is covered by a protective sheath called
a. Scutellum
b. Coleorhiza
c. Coleoptile
d. Tegmen.

Answer 1

Hint: Plumule is nothing but the bud of a young plant, where the embryo gives to the portion of the plant, where first true leaves are formed, above the level of cotyledons.

Complete answer:
- Plumule is the part of the seed embryo, where it germinates to shoot and produce the first true leaves of the plants.
- In the germinating seed, cotyledons grow first in the soil.
- After the growth of the cotyledon inside the soil, the plumule starts growing out of the soil.
- In some plants like sunflowers, where the seeds of sunflowers during germination produce the plumule, which is usually small conical shaped without any leaf structure.
- Based on the growth of cotyledon above the soil, and below the soil, germination is classified into two types.
- They are epigeal germination, in which the plumule growth occurs only if the growth of cotyledons is above the soil.
- Whereas hypogeal germination is that plumule growth occurs, even the cotyledon is within the soil.
- Whereas the shoot and true leaves that appear as plumule are covered by a protective sheath called coleoptile, it is mainly present in monocots, for example, grasses, where the shoot is covered by a thin moisturized sheath.
- When going to other options, scutellum is modified cotyledon seed, present as shield ex: rice seed.
- The part of the stem of the embryo plant, which is present beside the stem is called Coleorhiza.
- Tegmen is one of the covering layers of the ovule.

Hence, the correct answer is option (C).

Note: Generally the newly formed Coleoptile, does not contain, any proto chlorophyll, that is the reason why the newly formed shoot is pale in color, however, some preemergent coleoptile accumulates the purple color anthocyanin pigments.