This MCQ was asked in MHT-CET 2010 Biology.
The correct answer to this questions is 4 nuclei. Almost all students write 5 as the answer. This is a very tricky question. Read below for explanation.
Explanation:
Key concept: At maturity, the two haploid polar nuclei fuse with each other to form a single secondary nucleus.
Thus, the nuclei participating in double fertilization are:
- Nucleus of male gamete with egg cell (first fertilization or syngamy)
- Secondary nucleus and other male gamete(second fertilization or triple fusion)
Commonly, students make the mistake of counting 3 nuclei in the second step(triple fusion) instead of 2.