Pollen tube Pollen tube A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. It acts as a conduit 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. In maize, this single cell can grow longer than to traverse the length of the pistil. Pollen tubes were first discovered by Giovanni Battista Amici. They are used as a model for understanding plant cell behavior. Research is ongoing to comprehend how
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