Pollination and fertilization are two distinct processes in the reproduction of plants.
Pollination is the transfer of pollen grains from the male reproductive organ (anther) to the female reproductive organ (stigma) of a flower. This can occur through various means, such as wind, water, or by the help of animals like bees, butterflies, or birds. The main purpose of pollination is to bring the male gametes (contained in the pollen grains) closer to the female gametes (contained in the ovules) for fertilization to occur.
Fertilization, on the other hand, is the fusion of the male and female gametes to form a zygote, which eventually develops into a seed. After pollination, the pollen grain germinates on the stigma and grows a pollen tube that extends down to the ovary. Through this tube, the male gametes travel to reach the ovules, where they fuse with the female gametes to form a zygote. This fusion of gametes triggers the development of the embryo and endosperm within the seed.
In summary, pollination is the transfer of pollen from the male to the female reproductive organs, while fertilization is the fusion of male and female gametes to form a zygote. Pollination is a prerequisite for fertilization to occur, as it brings the male gametes in close proximity to the female gametes.