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

Explanation

(a) The process of fusion of haploid or diploid nuclei three times is called triple fusion.
(b) Triple fusion occurs in the embryo sac.
(c ) It involves the fusion of two polar nuclei to form a secondary nucleus, one male gamete with egg. To form a zygote and further diploid secondary nucleus with another male gamete to form PEN.