Pollen tube by recognition and hydration of the pollen that allows for germination of the tube and ultimate growth. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube. There is competition in this step as many pollen grains may compete to reach the egg. The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. Some plants have mechanisms in place to prevent
The X from Outer Space Guilala is finally defeated by jets laden with bombs, which coat it in a substance called "Guilalalium." It causes Guilala to shrink down to its original spore form. The government promptly launches the spore back into space, where it will circle the sun in an endless orbit. "The X From Outer Space" was released in Japan on 25 March 1967. "The X From Outer Space" was never released theatrically in the United States, and was released directly to television by American International Television in 1968. The Criterion Collection released "The X from Outer Space" on DVD in a compilation titled