Definitions for "POLLEN TUBE"
A tube that grows from a pollen grain on the stigma of a flower down through the style into the ovary.
When a pollen grain lands on the stigma of a flower, it is stimulated to produce a pollen tube. This is an outgrowth of the inner membrane of the pollen grain, and burrows its way through the tissue of the stigma, the style and then the ovary. Eventually the tip of the pollen tube finds its way through the small hole in the integuments surrounding the ovule and penetrates it. As the tube grows, the contents of the pollen grain - essentially genetic material - passes down the tube. When the tip of the tube enters the ovule, the genetic material flows into the ovule and fuses with the genetic material of the female gamete. This fertilisation results in an embryo plant. The pollen tube requires very specific conditions to germinate; this helps to make sure the pollen grain and the stigma are of the same species, and so no cross-species reproduction takes place.
slender tubular outgrown from a pollen grain that penetrates the ovule and releases male gametes