Question

An ovule of Cycas has archegonia
A. One
B. Two
C. Eight
D. Three to six

Answer 1

Hint: Cycas is an evergreen perennial plant. It belongs to the family Cycadaceae. It forms microsporophylls and megasporophylls for reproduction. It is a gymnosperm plant. It is one of several species used for the production of sago, as well as an ornamental plant.

Complete step by step answer: Archegonia is the female reproductive organ present in mosses and ferns. Some gymnosperms also possess this organ. It is an organ that has the shape of a flask consisting of a neck and the swollen base. The archegonia present in Cycasranges from three to six. It is present inside the female gametophyte. The archegonia are developed in the micropylar end of the female gametophyte. Each cell of the archegonia is developed from a cell known as an archegonial initial. An archegonium upon maturation has two neck cells and an egg. The life cycle of Cycas is diplohaplontic because it has both diploid and haploid phases, that is 2n and n chromosome numbers in their lifetime. The alteration in a generation is heterologous because the sporophyte (n) and gametophyte (n) exhibit differences in morphology. These species are endemic to India and about 113 Cycas species have been accepted.

Note: In Cycas, sporophyte represents the dominant and independent generation and the gametophyte is inconspicuous and short-lived. A gametophyte which upon complete development includes a stalk cell, prothallium cells, two male gametes and a stalk cell. Upon fertilization, the zygote develops a wall around it and gets converted into an oospore. Later undergoes differentiation and forms the pro embryo.