Question

Describe with the help of three labelled diagrams the different embryonic stages that include mature embryo of dicot plants.

Answer 1

Development of embryo:

The zygote starts dividing and gives rise to proembryo. This proembryo further divides, forming a globular, heart-shaped and mature embryo.
Following are the steps that occur during the development of embryo:

• The embryo develops at the micropylar end of the embryo sac where the zygote is situated.

• First, the zygote gives rise to proembryo and, then, to the globular, heart-shaped, mature embryo.

• A typical dicot embryo consists of an embryonal axis and two cotyledons.

• The portion of the embryonal axis above the level of cotyledons is called epicotyl. It contains the plumule (shoot tip). The portion below the axis is called hypocotyl. It contains the radicle (root tip). The root tip is covered by the root cap.