Question

The portion of the embryonal axis above cotyledon is called as
A) Epicotyl
B) Hypocotyl
C) Coleoptile
D) Radicle

Answer 1

Hint: Cotyledon is a significant part of the embryo in the seed of a plant and is known as an embryonic leaf in seed-bearing plants. The number of cotyledons present is one of the features used by botanists to classify flowering plants.

Complete answer:
The embryonic axis separates the embryo or immature plant into regions by use of the embryonic axis region. The section of the embryonic axis situated above the cotyledon point of attachment is called the epicotyl, which is expected to become the shoot. The part of the embryonic axis found in a dicot embryo above the cotyledon is known as the epicotyl.

The epicotyl is part of a seedling, the point just above the cotyledons or the seed leaves along with the embryonic shoot, finishing with the plumule, which rises to become the first true leaves. Epicotyls are present in flowering or angiosperm plants. In hypogeal germination, the epicotyl is responsible for breaking up the soil crust.

The part of the embryonic axis below the cotyledon in the embryo of a dicot is known as the hypocotyl. It finishes with a radicle.

Coleoptile is the pointed protective sheath protecting the developing shoot. There are two vascular bundles for coleoptiles, one on each side.

During the germination process, the radicle is the first component of a seedling to grow from the seed. It is the plant's embryonic root which develops downwards in the soil. The embryonic stem or hypocotyl is above the radicle, which protects the cotyledon. It is within the seed, the embryonic root.

Hence the correct answer is option ‘A’.

Note: Epicotyls are present in flowering or angiosperm plants. In hypogeal germination, the epicotyl is responsible for breaking up the soil crust. Hypogeal germination ensures that the cotyledons remain below the ground.