when you combine an egg with the material in pollen you get
Pollen tube Once a pollen grain settles on a compatible pistil, it may germinate in response to a sugary fluid secreted by the mature stigma of certain plants. Lipids at the surface of the stigma may also stimulate pollen tube growth for compatible pollen. Plants that are self-sterile often inhibit the pollen grains from their own flowers from growing pollen tubes. The presence of multiple grains of pollen has been observed to stimulate quicker pollen tube growth in some plants.[citation needed] The vegetative cell then produces the pollen tube, a tubular protrusion from the pollen grain, which carries the sperm cells within its cytoplasm. The sperm cells are the male gametes that will join with the egg cell and the central cell in double fertilization.
Gamete Plants which reproduce sexually also have gametes. However, since plants have an alternation of diploid and haploid generations some differences exist. In flowering plants the flowers use meiosis to produce a haploid generation which produce gametes through mitosis. The female haploid is called the ovule and is produced by the ovary of the flower. When mature the haploid ovule produces the female gamete which are ready for fertilization. The male haploid is pollen and is produced by the anther, when pollen lands on a mature stigma of a flower it grows a pollen tube down into the flower. The haploid pollen then produces sperm by mitosis and releases them for fertilization.