Triple fusion is the process that takes place in the angiospermic plant. In this process, there is the fusion of the male gamete with two polar nuclei inside the embryo sac of the angiosperm. Out of the two male gametes, one gamete fuses with the nucleus of the egg cell to form the zygote. The other male gamete fuses with the two polar nuclei to form a triploid endosperm nucleus. It results in the formation of the endosperm.