Explanation:

Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). ... The pollen tube proceeds to release the two sperm in the megagametophyte.

Answer:

During double fertilisation, pollen tube with two male gametes and tube nucleus enters the embryo sac on reaching the ovule, through the micropylar end. ... The other male gamete fuses with the egg nucleus causing fertilisation, resulting in the formation of a diploid zygote or diploid oospore. This is called syngamy.The process of fusion of one male gamete with the egg along with the union of the second male gamete with the two polar nuclei or the secondary nucleus is called double fertilisation. Out of the two male gametes, one fuses with the egg to carry out generative fertilisation or syngamy