Pollen cell. In flowering plants the vegetative tube cell produces the pollen tube, and the generative cell divides to form the two sperm cells. Pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see electron micrograph, right). Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the forget-me-not ("Myosotis" spp.), is around 6 µm (0.006 mm) in diameter. Wind-borne pollen grains can be
Chemical Agent Resistant Coating combined to produce a cured paint film. The materials were designed for resistance to windblown dust, sand and chemical agents. An improvement to solvent-borne polyurethanes, MCU materials offered both lower levels of volatile organic compounds and elimination of hazardous air pollutants. 2) Two-component, high-performance, water-reducible polyurethane: Waterbased CARCs, most commonly used by the military, were composed of water-reducible polyurethane resins, marking the first time a water-based two-component CARC was commercially available. This formulation eliminated several solvents, including methyl isobutyl ketone, toluene and xylene. Citation Chemical Agent Resistant Coating Chemical Agent Resistant Coating is a paint commonly applied to military vehicles