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
Pollen tube During pollen tube growth, DNA damages that arise need to be repaired in order for the male genomic information to be transmitted intact to the next generation. In the plant "Cyrtanthus mackenii", bicellular mature pollen contains a generative cell and a vegetative cell. Sperm cells are derived by mitosis of the generative cell during pollen tube elongation. The vegetative cell is responsible for pollen tube development. Double-strand breaks in DNA that arise appear to be efficiently repaired in the generative cell, but not in the vegetative cell, during the transport process to the female gametophyte. Pollen tube A pollen tube