Flower scent and color. Still other flowers use mimicry to attract pollinators. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Flowers are also specialized in shape and have an arrangement of the stamens that ensures that pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant (such as nectar, pollen, or a mate). In pursuing this attractant from many flowers of the same species, the pollinator transfers pollen to the stigmas—arranged with equally pointed precision—of all of the flowers it visits. Anemophilous flowers use the
Pollen tube the pollen tube responds to extracellular guidance signals to achieve fertilization. Pollen tubes are produced by the male gametophytes of seed plants. They act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. Pollen tubes were first discovered by Giovanni Battista Amici. Pollen tube formation is important for sexual reproduction to occur in seed plants. Plants have separate structures such as microsporocytes and megasporocytes and the pollen grains are transported to the female gametophyte