Embryogeny in Monocotyledons - Practice Questions & MCQ

Embryogeny in Monocots:

• The zygote elongates and then divides trans­versely to form basal and terminal cells. 
• The basal cell (towards the micropylar end) produces a large swollen, vesicular suspensor cell. It may function as haustorium. 
• The terminal cell divides by another transverse wall to form two cells.
• The top cell after a series of divisions forms plumule and a single cotyledon. 
• Cotyledon called scutellum grows rapidly and pushes the terminal plumule to one side.
• The plumule comes to lie in a depression.
• The middle cell, after many divisions, forms hypocotyl and radicle. It also adds a few cells to the suspensor. 
• In some cereals both plumule and radicle get covered by sheaths developed from scutellum called coleoptile and coleorhiza respectively.

Structure of Monocot Embryo:

• The embryos of monocotyledons have only one cotyledon. 
• In grass family (Gramineae), this cotyledon is called scutellum. 
• It is situated towards the lateral side of the embryonal axis. 
• This axis at its lower end has a radical and root cap enclosed in a sheath called coleorhiza.
• The part of the axis above the level of attachment of scutellum is called epicotyl. 
• It has as shoot apex and few leaf primordia enclosed in a hollow foliar structure called coleoptile.
•  Epiblast represents rudiments of the second cotyledon.