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Eight nucleated embryo sac is a :
A
Only monosporic
B
Only bisporic
C
Only tetrasporic
D
Any of the above
Detailed Solution
An embryo sac with 8 nuclei (7 cells) can develop in different ways:
Monosporic (Polygonum type, most common): from one functional megaspore after three mitotic divisions.
Bisporic (Allium type): from two megaspore nuclei.
Tetrasporic (e.g. Adoxa, Fritillaria): from all four megaspore nuclei.
In each of these types, the mature embryo sac can be 8-nucleate.
So an eight-nucleated embryo sac can be any of the above.
Monosporic (Polygonum type, most common): from one functional megaspore after three mitotic divisions.
Bisporic (Allium type): from two megaspore nuclei.
Tetrasporic (e.g. Adoxa, Fritillaria): from all four megaspore nuclei.
In each of these types, the mature embryo sac can be 8-nucleate.
So an eight-nucleated embryo sac can be any of the above.