Pollen a net like appearance consisting of elements (murus, muri) separated from each other by a lumen (plural lumina). The pollen wall protects the sperm while the pollen grain is moving from the anther to the stigma; it protects the vital genetic material from drying out and solar radiation. The pollen grain surface is covered with waxes and proteins, which are held in place by structures called sculpture elements on the surface of the grain. The outer pollen wall, which prevents the pollen grain from shrinking and crushing the genetic material during desiccation, is composed of two layers. These two layers
Coil coating Coil coating Coil coating is the continuous and highly automated industrial process for efficiently coating coils of metal. Because the metal is treated before it is cut and formed, the entire surface is cleaned and treated, providing tightly-bonded finishes. (Formed parts can have many holes, recessed areas, valleys, and hidden areas that make it difficult to clean and uniformly paint.) Coil coated metal (often called prepainted metal) is often considered more durable and more corrosion-resistant than most post painted metal. Annually, 4.5 million tons of coil coated steel and aluminum are produced and shipped in North America, and 5 million