Name: Pollen-Pistil Interaction
Uploaded: 2019-07-19
Duration: 4 min 55 s
Description: Pollen Pistil interactions are the sequence of events that are decisive in the selection of apt pollen for maintaining genetic diversity. Comprehend this dyn...

Question

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

Accepted Answer

In plants, the embryo is formed from a diploid zygote, the product of the fusion of gametes during fertilization. The zygote divides transversely to form a two-celled pro-embryo. The cell towards the micropyle is known as the basal cell and the other is known as a terminal cell.
The basal cell towards the micropyle undergoes several transverse divisions to form a long suspensor. The terminal cell divides longitudinally twice to form four cells and this stage is called quadrant stage. The four cells of the quadrant stage now divide transversely to form an octant stage of eight cells arranged in two tiers of four cells. The lower tier gives rise to the stem tip and cotyledons, while the upper tier is meant for the formation of the hypocotyl.

The formation of hypocotyl is followed by periclinal division in the octant cells to give rise to eight outer cells, and eight inner cells. The eight outer cells form the dermatogen, which divides anticlinally and develops into the epidermis.
The inner cells form the periblem which develops into cortex and plerome from which stele is formed. The basal cell divides repeatedly to form a long suspensor of six to ten cells.
The lowermost cell of the suspensor is known as hypophysis. It gives rise to root cap, epidermis, and cortex of the root, by repeated divisions.

Further growth of hypocotyl and cotyledon causes curvature of the cotyledons and the embryo at this stage appears as a horse-shoe shaped structure. In the mature embryo, the stem tip is terminal in position, and the two cotyledons occupy the lateral position.

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

Important Questions on Sexual Reproduction in Flowering Plants

Learn and Prepare for any exam you want !