Question

What is embryonal axis?

Answer 1

Hint: The dicotyledons, also referred to as dicots (or more rarely dicotyls), are one among the two groups into which all the flowering plants or angiosperms were formerly divided. The name refers to at least one of the standard characteristics of the group, namely that the seed has two embryonic leaves or cotyledons.

Complete answer:
The embryonal axis divides the embryo or immature plant into regions by the help of embryonal axis region, this region becomes stem of the plant when the plant gets matured. A eudicot embryo consists of an embryonic axis attached by two cotyledons and in monocots it is attached by single cotyledon.
A typical dicotyledonous embryo, consists of an embryonal axis and two cotyledons.

The Embryonal axis has two main parts:
Epicotyl: The portion of embryonal axis above the level of cotyledons which terminates into stem tip or plumule. An epicotyl is vital for the beginning stages of a plant's life. It's the region of a seedling stem above the stalks of the seed leaves of an embryo plant. It grows rapidly, showing hypogeal germination, and extends the stem above the soil surface. a standard misconception is that the epicotyl, being closer to the apex of the plant, is that the first part to emerge after germination - rather, the hypocotyl, the region of the stem between the purpose of attachment of the cotyledons and therefore the root - forms a hook during hypogeal germination and pushes out of the soil, allowing the more delicate tissues of the plumule and apical meristem to avoid damage from pushing through the soil.

Hypocotyl: The cylindrical portion below the level of cotyledons which terminates into root tip or radicle. The part of a plant embryo or seedling that lies between the radicle and therefore the cotyledons. Upon germination, the hypocotyl pushes the cotyledons above the bottom to develop. It eventually becomes a part of the plant stem. Most seed-bearing plants have hypocotyls, but the grasses have different, specialized structures.

Note: Parts of typical dicot embryo include- Plumule, cotyledons, hypocotyl, radical, and plant organ. A typical dicotyledonous embryo consists of an embryonal axis and two cotyledons. The portion of the embryonal axis above the extent of cotyledons is that of the epicotyl, which terminates with the plumule or stem tip.