Original: The pollen tube of most seed plants acts as a conduit to transport sperm cells from the pollen grain , either from the stigma ( in flowering plants or angiosperms ) to the ovules at the base of the pistil , or directly through ovule tissue in some gymnosperms ( conifers and gnetophytes ) .
Simplified: It transports sperm cells from the pollen grain , from the stigma ( in flowering plants or angiosperms ) to the ovules at the base of the pistil . In some gymnosperms ( conifers and gnetophytes ) sperms move directly through ovule tissue .