It is a process involved in the sexual reproduction of angiosperms. Triple fusion is a fusion that involves a sperm nucleus and two polar nuclei which occurs in the double fertilization in a seed-bearing plant that results in the endosperm formation. The fusion process occurs in the embryo sac of the angiosperms. In the event of fertilization, when the stigma comes in contact with the pollen grains, it germinates, giving rise to the pollen tube which enters the ovule through the style.
This pollen tube then enters into one of the synergids, post which two male gametes are released. One of the two male gametes fuses with the nucleus of the egg cell to produce the zygote, this process is referred to as syngamy. A primary endosperm nucleus, triploid in nature is formed when the other male gamete combines with the two polar nuclei that are located in the central cell. Since the process is involving the combining or fusing of three haploid nuclei, it is referred to as triple fusion. The end result, outcome of the process of triple fusion is the formation of endosperm. During the process of triple fusion, endosperm development of three types are noticed, which are as follows:
- Cellular endosperm development – Example – Coconut meat
- Nuclear endosperm development – Liquid endosperm is developed from nuclear endosperm development such as Coconut water
- Helobial endosperm development – Monocots
The main difference between triple fusion and double fertilization is that in double fertilization, the embryo sac and two sperm cells fuse, whereas the sperm nucleus and two polar nuclei fuse in the central cell of the embryo sac in the process of triple fusion. To know more about triple fusion, double fertilization, and related topics, please register at BYJU’S.