Question

From the statements given below choose the option that are true for a typical female gametophyte of a flowering plant:

i. It is 8-nucleate and 7-celled at maturity
ii. It is free-nuclear during the development
iii. It is situated inside the integument but outside the nucellus
iv. It has an egg apparatus situated at the chalazal end

• A. ii and iii
• B. ii and iv
• C. i and ii
• D. i and iv

Answer 1

The correct option is C i and ii

Location

The embryo sac is within the integuments. Nucellus surrounds the embryo sac

Structure

A typical female gametophyte of a flowering plant at maturity is composed of seven cells and eight nuclei.

* Egg apparatus with one egg and two synergid cells present towards the micropylar end.

* Three antipodal cells present towards the chalazal end.

* Two central polar nuclei and remain free until fertilisation by male gametes


Development

During megasporogenesis (in the formation of an embryo sac from the megaspore), the nuclear divisions (karyokinesis) are not followed immediately by cell-wall formation (cytokinesis). Thus the embryo sac is free-nuclear during development.


Final answer

(c) i and ii