DOUBLE OR TRIPLE FERTILIZATION

Fertilization is defined as the fusion of dissimilar male gamete and female gametes to form zygote which eventually develops into embryo . 

The process of fertilization was first described by Strasburger in Monotropa in 1884.

But the mechanism of double fertilization was discovered by Nawaschin in 1898 during this experiment on fertilllaria and hillium plant it was supported by Guignard .

When the 2 male gametes are discharged into the embryosac the fusion of gametes takes place.

out of these two male gametes one fuses with the haploid polar nuclei or diploid secondary nucleus of the central cell to form triploid primary endosperm nucleus .As three nucleus are involved in the fusion process it is called as triple fusion.

In angiospermic two acts of fertilization occurs in the same embryosac i.e. one is generative fertilization and other vegetative fertilization .So this phenomenon is known as double fertilization .

Double fertilization is defined as the fusion of two male gametes brought by a pollen tube to two different cells of the same female gametophyte in order to produce two different structure .

One male gamete fuses with the egg to form a diploid zygote where as the other male gamete fuses with the diploid secondary nucleus of the central cell to form a triploid primary endosperm nucleus which later develops into  primary endosperm cell.

So double fertilization involves both syngamy and triple fusion five nuclei are involved in this process i.e. two in syngamy and three in triple fusion .

It is an unique and universal feature of angiosperms except in family orchidaceal , podostemauwe and trapacsal.