What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.


Triple fusion – The process of fusion of the male gamete with the two polar nuclei inside the central cell located in the embryo-sac to form primary endospermic nucleus (PEN) is called triple fusion. The process takes place inside the embryo-sac.


This process takes place in the following steps –


• When the pollen grains fall on the stigma of a flower, they germinate and give rise to the pollen tube.


• The pollen tube passes through style and enters the embryo-sac from the micopylar end.


• One of the male gamete fuses with egg cell to form zygote (syngamy)


• The second male gamete fuses with the two polar nuclei present in the central cell and form triploid primary endosperm nucleus.


• This process involves the fusion of three haploid nuclei hence is known as triple fusion.


One male gamete nucleus and two polar nuclei are involved in this process.


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