Question

The given diagram represents the female gametophyte of angiosperms. Answer the following:
(i) Name the parts - A, B, C. 
(ii) Function of filiform apparatus.
(iii) Part that forms PEN.
(iv) Ploidy of antipodals. 

 

Hint:

The mature angiosperm embryo sac is "7-celled but 8-nucleate" because the large central cell contains two polar nuclei.

Answer 1

i. Identification: Based on a standard 7-celled, 8-nucleate embryo sac:
A: Antipodal cells (located at the chalazal end).
B: Central cell (containing polar nuclei).
C: Egg cell (part of the egg apparatus at the micropylar end).
ii. Function of filiform apparatus: These finger-like projections in the synergids guide the entry of the pollen tube into the synergid.
iii. Formation of PEN: The secondary nucleus (formed by the fusion of two polar nuclei in the central cell) fuses with the second male gamete to form the Primary Endosperm Nucleus (PEN).
iv. Ploidy of antipodal cells: They are haploid ($n$).