Module: | Pre-fertilization: Micro/Megasporogenesis
Q17: Consider the following statements regarding the mechanics of syngamy and triple fusion:
1. Syngamy involves the fusion of one male gamete with the egg cell to form a diploid zygote.
2. Triple fusion involves the second male gamete fusing with the two polar nuclei in the central cell to form a triploid primary endosperm nucleus (PEN).
3. Double fertilization, which encompasses both syngamy and triple fusion, is a characteristic feature unique to all gymnosperms and angiosperms.
Which of the above statements is/are correct?
2. Triple fusion involves the second male gamete fusing with the two polar nuclei in the central cell to form a triploid primary endosperm nucleus (PEN).
3. Double fertilization, which encompasses both syngamy and triple fusion, is a characteristic feature unique to all gymnosperms and angiosperms.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, while Statement 3 is incorrect.
When the pollen tube enters the synergid, it releases two male gametes.
Syngamy is the first fertilization event where one haploid male gamete fuses with the haploid egg cell to generate a diploid (2n) zygote, which will develop into the embryo.
Simultaneously, the other haploid male gamete moves to the central cell and fuses with the two haploid polar nuclei (or the secondary nucleus if already fused) to produce a triploid (3n) primary endosperm nucleus (PEN). Because two separate fusion events occur in the same embryo sac, the phenomenon is termed double fertilization.
Statement 3 is incorrect because double fertilization is exclusively the hallmark of angiosperms (flowering plants) and is generally absent in gymnosperms, whose endosperm forms before fertilization and is haploid.
When the pollen tube enters the synergid, it releases two male gametes.
Syngamy is the first fertilization event where one haploid male gamete fuses with the haploid egg cell to generate a diploid (2n) zygote, which will develop into the embryo.
Simultaneously, the other haploid male gamete moves to the central cell and fuses with the two haploid polar nuclei (or the secondary nucleus if already fused) to produce a triploid (3n) primary endosperm nucleus (PEN). Because two separate fusion events occur in the same embryo sac, the phenomenon is termed double fertilization.
Statement 3 is incorrect because double fertilization is exclusively the hallmark of angiosperms (flowering plants) and is generally absent in gymnosperms, whose endosperm forms before fertilization and is haploid.