Question

Define triple fusion. What is the product of this process? What does the product develop into?

Answer 1

Triple fusion is the process that occurs in the angiosperms (flowering plant) which takes place during the process of syngamy (fertilization of male and female gametes). It is one of the results of double fertilization that takes place in flowering plants.

Complete Answer:
- Triple fusion is the process in which other male gametes move two haploid polar nuclei (i.e. located in the central cell) and thus forming the triploid structure called as primary endosperm nucleus (PEN).

- When one male gamete fuses with one female gamete then the process is known as syngamy and the product is called as zygote that at last, it turns into the product called as fruit. The other male gamete(haploid nucleus i.e. n) moves towards the two polar nuclei(two haploid nucleus i.e. n+n) that are located in the central cell thus forming the triploid structure called as PEN. Since both the process i.e. syngamy and triple fusion takes place in an embryo sac thus the phenomena is called as double fertilization, that is exclusively occurs in the flowering plants i.e. in angiosperms.

- The central cell after triple fusion turns into a primary endosperm cell (PEC) and the product produced by this process is called as endosperm while the zygote (result of syngamy) develops into an embryo.

- Endosperm produced as a result of triple fusion is involved in the post fertilization events i.e. embryogenesis. During this process, the zygote needs nutrition for its proper growth and development. The endosperm acts as a reserve food material and thus used for the nutrition of the developing embryo and gets vanished. The endosperm acts as a source of starch though it also contains oil.

Note: The endosperm is of three types:
- Free nuclear endosperm: found in coconut water.
- Cellular endosperm: found in the kernel of coconut.
- Helobial endosperm: found in monocot plants.