Eight nucleated embryo sac is
- only monosporic
- only bisporic
- only tetrasporic
- any of these.
Answer
(4) any of these.
Solution
As per NCERT, in a majority of flowering plants one of the four megaspores is functional; its nucleus divides mitotically three times to form the 8-nucleate, 7-celled embryo sac (monosporic development).
∵ An 8-nucleate embryo sac is also formed when two megaspore nuclei take part (bisporic type, e.g. Allium) or when all four megaspore nuclei take part (tetrasporic type, e.g. Adoxa),
∴ an eight-nucleated embryo sac may be monosporic, bisporic or tetrasporic.
Answer: (4)