Question

Describe the sequence of events as a dicot zygote becomes an embryo enclosed within a seed.

Answer 1

1. The zygote divides transversely, forming a small apical cell and a large basal cell.
2. The apical cell divides longitudinally twice to form a quadrant, then cells divide transversely to form an octant.
3. The octant’s upper tier forms the hypocotyl; the lower tier forms the epicotyl, cotyledons, and plumule.
4. The basal cell divides to form a suspensor of 6-10 cells, which supports the embryo.
5. The apical portion develops into the pro-embryo, progressing through globular and heart-shaped stages.
6. Two cotyledons become distinct; the plumule and radicle differentiate.
7. The suspensor degenerates and the mature embryo is formed in the seed.

This process is embryogenesis in dicots, leading to a seed with a mature embryo ready for germination.