Question

Early embryogeny in Cycas is characterized by

• A. Absence of suspensor cell
• B. Presence of expanded free nuclear division
• C. Reduced free nuclear division
• D. Many cotyledons

Answer 1

The correct option is B Presence of expanded free nuclear division

Early embryogeny in Cycas is characterized by presence of expanded free nuclear division. The zygote, which is the first sporophytic cell, undergoes free nuclear divisions. The interval between pollination and fertilization is several months in Cycas.
The zygote (2n) secretes cell wall and becomes the oospore. The zygote or oospore is the first cell of sporophyte generation. The oospore undergoes free nuclear division followed by wall formation to form a small cellular mass called pro-embryo. The pro-embryo differentiated into a basal embryonalzone, middle suspensor and upper haustorium. The haustorial region remains in contact with the free-nuclear region and soon disappear.