Pollenkitt - Pollen Wall
The lipoidal layer found on the outside of the mature pollen grains of many insect pollinated species is known as the pollenkitt. In addition to lipids it is made up of flavonoids, carotenoids and degeneration products of tapetal proteins. The carotenoids are responsible for its characteristic yellow or orange color. The function of pollenkitt is not clear. It is believed to act as an insect attractant, help in pollen dispersal and in protecting against the damaging effects of UV rays. Deposition o flavonoids appear important for the nod functioning of pollen. In maize it has been shown that the pollen grains that lack flavonoids are incapable of developing tubes that are effective in fertilization. Lipids also help in checking water loss after anther dehiscence and discharge of pollen.