Final answer:
When pollen is dropped in a flower, it grows a pollen tube, which is essential for plant reproduction and allows the generative cell within the pollen grain to travel to the ovary and fertilize the egg cell.
Step-by-step explanation:
When pollen is dropped in a flower it grows a pollen tube which goes down into the flower. The pollen tube is a crucial part of plant reproduction and forms when a pollen grain adheres to the stigma of a flower. Within the pollen grain, there is a tube cell and a generative cell. After the pollen lands on the stigma, the tube cell grows into the pollen tube, which penetrates through the style to reach the female gametophytes inside the ovary.
The generative cell travels down this tube and divides to form two sperm cells. One of the sperm cells fuses with the egg cell to produce the zygote, while the other sperm cell fuses with the polar nuclei to form the endosperm, in a process known as double fertilization. This series of events leads to the formation of a diploid zygote and eventually the development of seeds within the fruit.