double fertilzation

The process in which the two sperm nuclei of a pollen grain unite with nuclei of the embryo sac of an angiosperm plant. One sperm nucleus unites with the egg to form the diploid zygote, from which the embryo develops. The other sperm unites with the two nuclei located in a single cell at the center of the embryo sac. Together these nuclei form the triploid nucleus of the cell from which the endosperm develops. Double fertilization in this form is unique to the angiosperms. Since a single polen grain has 2 sperm. Double fertilization occurs when 1 of these sperm combines with the egg, and the other sperm combines with a cell (this is called endosperm) That is in order for the seed to keep being produced.Seed has to be germinated, and without the extra sperm (double fertilization) the plant couldn't germinate and would go extinct.




 


http://en.wikipedia.org/wiki/Double_fertilization
http://www.biologyjunction.com/images/doublefertilazation.jpg

http://bcs.whfreeman.com/thelifewire/content/chp39/3902001.html