The molecule will enter the cell using a channel protein.
Fertilization is done by germination of pollen on the pistil, without need of moisture as in the case of ferns (character they share with other Spermaphytes).
In Angiosperms fertilization has three essential characteristics:
* it is siphonogamous: the apertured pollen grain possessing two or three cells sees its vegetative cell germinate and form a pollen tube which will convey, with the help of its cytoskeleton, the male gamete (case of the tricellular pollen) where the generating cell ( case of the bicellular pollen) which will carry out its second division of meiosis. In this siphonogamy corresponds to a total franking of water for fertilization.
* it is anisogamous: the female gamete is by far the most massive of the two (the pollen grain is often very dehydrated, the cells it contains have a very small cytoplasmic space).
* it is double: the male gametes conveyed by the pollen grain will merge their nuclei (caryomixis) with those of two different cells. It's a special function for the reproduction of angiosperms. The pollen grain contains two nuclei (all haploids), whereas for example the mammalian spermatozoa contains only one.
Regions containing metapopulations are created by the birth and immirgration of organisms to those regions.
Through evaporation water moves from the biosphere to the atmosphere.
