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
Water-based pipe coating pipe flanges and fittings, gray iron pipe (sewer lines), storm water sealing, utility box sealing, and septic tank and vault sealing. Water-based pipe coating A water-based pipe coating is an environmentally friendly coating that is applied to the inner and outer surfaces of ductile iron pipe. The coating serves to protect the water supply lines from corrosion whether from the outside or the inside. It also serves to protect the drinking water from contamination. The coating is an emulsion manufactured using asphaltene and water primarily, with other raw materials according to the manufacturer’s specifications. Water-based coatings began development in the