Question
Question: Shoot or stem develops from A. Plumule B. Radicle C. Both of (A) and (B) D. None of the abov...
Shoot or stem develops from
A. Plumule
B. Radicle
C. Both of (A) and (B)
D. None of the above
Solution
The shoot or stem of a plant develops from that part of the seed embryo which is positively phototropic i.e., moves upwards in response to the light stimulus. It is located above the cotyledons and it does not grow until the cotyledons have grown above the ground.
Complete answer:
Option (A) is correct. Plumule develops into the shoot or stems bearing first true leaves and is also known as the future shoot of a plant. It is positively phototropic which means it grows in response to a light stimulus i.e., upwards.
Option (B) is incorrect. Radicle develops into the root of a plant and is also known as the future root of a plant. It is positively geotropic which means it grows in the direction of gravity i.e., downwards.
Option (C) is incorrect. Both options i.e., (A) and (B) are not correct. Only option (A) is correct while option (B) is incorrect because the shoot or stem develops from the plumule and the root develops from the radicle.
Option (D) is incorrect. The alternative “none of the above” is not correct because one of the options is correct, i.e. option (A) which implies that the plumule gives rise to the shoot or stem of a plant.
Hence, the correct answer is option (A).
Note: A seedling is a young sporophyte that develops out of the embryo from a seed. It consists of three parts: radicle, plumule, and cotyledons. In dicot seeds, the plumule is terminal, cotyledons are lateral in position; therefore germination is usually hypogeal or epigeal while in monocot seeds, the plumule is lateral, the cotyledon is terminal; therefore germination is usually hypogeal.