List the changes observed in angiosperm flower subsequent to pollination and fertilization.

I. After pollination :
* Pollen grain germinate on stigma and pollen tube is formed.
* Inside the pollen tube generative cell divides and produce two male gametes.
* Pollen tube grows through the tissues of the stigma and style and reaches the ovary by different methods.
* Pollen tube enters into ovules through different methods i.e porogamy, mesogamy and chalazogamy.
II. After fertilization :
* After fertilization sepals, petals and stamens wither and fall off.
* Zygote develops into embryo. ovary into fruit and ovules into seeds.
* PEN develops into endosperm, nucellus develops into perisperm.