Pollen is a fine to coarse powder containing the microgametophytes The gametophyte produces male or female gametes , by a process of cell division called mitosis. The fusion of male and female gametes produces a diploid zygote, which develops by repeated mitotic cell divisions into a multicellular sporophyte. Because the sporophyte is the product of the fusion of two haploid gametes, its cells are diploid, of seed plants The spermatophytes (also known as phanerogams) comprise those plants that produce seeds. They are a subset of the embryophytes or land plants. The living spermatophytes form five groups:, which produce the male gametes A gamete is a cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete — called an ovum (or egg) — and (sperm cells). Pollen grains have a hard coat that protects the sperm cells during the process of their movement between the stamens The stamen is the male organ of a flower. Each stamen generally has a stalk called the filament (from Latin filum, meaning "thread"), and, on top of the filament, an anther (from Ancient Greek anthera, feminine of antheros "flowery," from anthos "flower"), and pollen sacs, called microsporangia. The development of the to the pistil The gynoecium is a term with several meanings in botanical usage. In reference to mosses; liverworts; and hornworts, gynoecium refers to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot. The more common use of gynoecium, however, is to refer to the ovule-producing part of a flower. The gynoecium in of flowering plants or from the male cone A cone is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from the fact that the shape to the female cone of coniferous plants. When pollen lands on a compatible pistil of flowering plants, it germinates Germination is the process in which a seed or spore emerges from a period of dormancy. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However, the growth of a sporeling from a spore, for example the growth of hyphae from fungal spores, is also germination. In a more general sense, and produces a pollen tube that transfers the sperm to the ovule of a receptive ovary. The individual pollen grains are small enough to require magnification to see detail.
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CO2 Science Magazine
Poaceae pollen in Galicia (NW Spain): characterization and recent trends in atmospheric pollen season. International Journal of Biometeorology 53: 333-344. ...
