Question

Where does the germination of the pollen grains take place and how?

Answer 1

Germination of the pollen grain takes place on the stigma (also called the pistol). It's amazing! The ovule (female) has these cells (synergids) that release calcium attracting the pollen grain ( male) and the pollen grain knows then to grow down towards this calcium source where also the ovule is waiting for it!!!!
The micropyle is the open end of the integument which surrounds the megasporangium (or zygote).
The corolla is the outside part of the plant and the anther is the "male" part of the plant!
Hope this helps!