Question

Double fertilization is fusion of :

• A. two eggs
• B. two eggs and polar nuclei
• C. one male gamete with egg and other with synergid
• D. one male gamete with egg and other with secondary nucleus

Answer 1

Answer: (D)

The double fertilization was discovered by S.G. Nawaschin $(1898)$ and Guignard in Lilium and Fritilaria. Double fertilization is restricted only to angiosperms. When pollen tube enters ovule, it strikes one of the synergid, and burst open to release the two male genetes which fuses with two different structures in the same female gametophyte. Thus double fertilization can be distinguished as :
1. Generative fertilization : Fusion of one male gamete with the egg producing diploid zygote or oospore.
2. Vegetative fertilization : Fusion of nucleus of second male gamete with the diploid secondary (fused) nucleus or the triple fusion i.e., fusion of one male nucleus and two polar nuclei forming endosperm $(3n)$.