Aperture (botany) Aperture (botany) Apertures are areas on the walls of a pollen grain, where the wall is thinner and/or softer. For germination it is necessary that the pollen tube can reach out from the inside of the pollen grain and transport the sperm to the egg deep down in the pistil. The apertures are the places where the pollen tube is able to break through the (elsewhere very tough) pollen wall. The number and configuration of apertures are often very exactly characteristic of different groups of plants. The biggest class of plant species, the Eudicots, usually have three apertures in each
Chemical Agent Resistant Coating Chemical Agent Resistant Coating Chemical Agent Resistant Coating is a paint commonly applied to military vehicles to provide protection against chemical and biological weapons. The surface of the paint is engineered to be easily decontaminated after exposure to chemical warfare and biological warfare agents. The paint is also resistant to damage and removal by decontaminating solutions. Two-component systems (e.g. epoxy or polyester-based) are often employed. This coating is described in MIL-DTL-53072E. As of 2018, the U.S. Army Research Laboratory (ARL) led research and development activity for CARC and was the approving authority of CARC products for the Department of Defense