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The arrangement of the nuclei in a normal embryo sac in the dicot plants is -
A
2 + 4 + 2
B
3 + 2 + 3
C
2 + 3 + 3
D
3 + 3 + 2
Detailed Solution
The normal embryo sac of most flowering plants is of the Polygonum type; it is monosporic, 7-celled and 8-nucleate.
It develops from the functional megaspore by three successive mitotic divisions, giving 8 nuclei.
At the micropylar end three cells form the egg apparatus: one egg cell and two synergids (3 nuclei).
In the centre is the large central cell with two polar nuclei (2 nuclei).
At the chalazal end are three antipodal cells (3 nuclei).
So the arrangement of the nuclei is 3 + 2 + 3.
It develops from the functional megaspore by three successive mitotic divisions, giving 8 nuclei.
At the micropylar end three cells form the egg apparatus: one egg cell and two synergids (3 nuclei).
In the centre is the large central cell with two polar nuclei (2 nuclei).
At the chalazal end are three antipodal cells (3 nuclei).
So the arrangement of the nuclei is 3 + 2 + 3.