Question

how does the process of fertilistion take place in flower

Answer 1

The sperm cells of a flowering plant are contained in pollen grains. Pollination occurs when pollen grains are transported from anthers to stigmas. After the pollen grains lands on stigma, a tube grows from the pollen grains through the style of the ovary. Inside the ovary ovules are present. Each ovule contains an egg. Sperm cells within the pollen grain move down the pollen tube into the ovule. Fertilisation occurs when one of the sperm cells fuse with the egg inside the ovule.

Answer 2

The flower consists of male and female part.
Female parts contain - stigma, style and ovary. And ovary contains ovule. Male parts contain - anther and stigma. Anther contains pollen grain.
When a pollen grain (male gamate) reach on stigma. Then it secrete some liquid substance. This liquid substance which is absorbed by stigma and then grow longer and longer, to form Pollen tube. The 2 male gamates travel through Pollen tube and ultimately reach the ovule of the ovary. Ovule contains egg. When one male gamate fuse with egg then it forms zygote and the other male gamate fuse with two polar nuclei then it is known as triple fussion. Formation of zygote in plants /flower is known as syngamy.
Since the fussion occurs two times. So, it is known as DOUBLE fertilization.
After this ovary develops into fruit and ovule develop into seed.

Hope it helps you.