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
Milky spore reproduction of the bacteria inside the grub. Within 7–21 days the grub will eventually die and as the grub decomposes, billions of new spores are released into the soil. Milky spore in the soil is not harmful to beneficial insects, birds, bees, pets, or people; and milky spore, like other bacteria, is highly survivable in drought conditions but suffers in temperatures of Zone 5 and colder. Milky spore Paenibacillus popilliae (formerly "Bacillus popilliae") is a soil-dwelling, Gram-positive, rod-shaped bacterium. It is responsible for a disease (commonly called milky spore) of the white grubs of Japanese beetles. The adult Japanese beetles