Pollen tube subsequent pollination (transfer of pollen grains to the pistil, the female reproductive organ). Transfer of pollen is usually carried out by wind, water, or animals . The ovaries hold the ovules that produce the female gamete: the egg cell, which waits in place for fertilization. Once a pollen grain settles on a compatible pistil, it may germinate in response to a sugary fluid secreted by the mature stigma. Lipids at the surface of the stigma may also stimulate pollen tube growth for compatible pollen. Plants that are self-sterile often inhibit the pollen grains from their own flowers from growing pollen
Compartmentalization of decay in trees compartmentalization. According to CODIT, when a tree is wounded cells undergo changes to form "walls" around the wound, slowing or preventing the spread of disease and decay to the rest of the tree. By increasing understanding of how trees respond to decay, CODIT has had many applications. For example, arborists are frequently called upon to analyze the danger posed to people or property by a damaged or decaying tree. By knowing how decay is likely to spread, such hazard tree analyses may be more accurate, thereby preventing unnecessary tree removal, property damage, or injury. For another example, in the production