Question

What are epicotyl and hypocotyl? How do they form and grow?

Answer 1

Hint: Epicotyl is the first part of the plant that emerge after the germination, where as it is important in the beginning stage of the plant life, whereas hypocotyl is the structure that can be observed in the seedling after the germination.

Complete answer:
Epicotyl:
- It is the region present in the seedling, which is present above and stalks the early formed leaves of an embryo plant.
- To say simply, in the physiology of the plants, epicotyl is the embryonic shoot which is present above the plants.
- So in almost all the plants, this structure finally develops into leaves of the plants
- This epicotyl in the dicot seeds usually show hypogeal germination, and this structure extends the forming stem above the surface of the soil.
- Generally this epicotyl ends with plumule.

Hypocotyl:
- It is the region on the stem, where it is present between the point of attachment of the cotyledons of the dicots and the roots
- To say in simple terms, hypocotyl is considered as a base stem which is present within the cotyledon, and shoots above the epicotyl.
- It forms a hook during the hypogeal germination, and it generally ends as a radicle.
- The hypocotyl in the monocots, grows out several inches and forms a green color leaf like structure.
- It is the transition zone between root and the shoot.

Note: In general most of the seed bearing Plants have hypocotyl, but some plants such as grasses, they have different and a specialized structure, and epicotyl is the structure which finally forms the first true leaves.