Question

Why is fertilization not possible without pollination?

Answer 1

Fertilization is the process of union or fusion of two gametes or cells that is male gamete and female gamete to produce zygote. Zygote then grows and develops to form a new individual. It Is a form of sexual reproduction in plants. This is done by many hormonal and structural development and sexual reproduction in flowering plants is called Embryology.

Complete Answer:
The flower is the organ of sexual reproduction in flowering plants. Inside the flower, male reproductive structure, called androecium and female reproductive structure called gynoecium are formed.
Androecium is the bundle of stamens together and The main structure of the female reproductive system is the stigma, ovule and embryo sac.
Pollination refers to the process of transfer of pollen from anther of stamen to the stigma of having ovules. This is done so that the content of pollen grains enter the ovule and fertilization takes place.
The pollen, after reaching the stigma produces the pollen tube through which the male gametes are transported to ovule and fertilization occurs.
If there is no pollination, then the male gametes of pollen grain cannot enter the ovule and hence fertilization cannot occur and formation of zygote is not achieved which results in the inhibition of sexual reproduction. Hence, pollination is required to achieve fertilization.

Note:
If we dust some pollen grains from flowers of pea, chickpea, on a glass slide and add some sugar solution to it and after 20 minutes, if we observe the pollen grains under microscope, we can see the pollen tubes coming out of pollen grains. All these processes require chemical coordination and are governed by hormones and surroundings.