Flower attract and use insects, bats, birds or other animals to transfer pollen from one flower to the next. Often they are 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. Many flowers rely on simple proximity between flower parts to ensure pollination. Others,
Pollen tube the two sperm cells. One of the sperm fertilizes the egg cell which develops into an embryo, which will become the future plant. The other one fuses with both polar nuclei of the central cell to form the endosperm, which serves as the embryo's food supply. Finally, the ovary will develop into a fruit and the ovules will develop into seeds. Gymnosperm pollen is produced in microsporangia borne on the scales of the male cone or microstrobilus. In most species the plants are wind-pollinated, and the pollen grains of conifers have air bladders that provide buoyancy in air currents. The