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Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life ...
A good predictor for when a plant will bloom and produce pollen is a calculation of the growing degree days. The color of pollen below indicates the color as it appears when the pollen arrives at the beehive. After arriving to the colony with a fresh load of pollen, the honey bee unloads its pollen from the pollen basket located on its hind legs.
The stamens borne on the hypanthium are the pollen-producing reproductive organs of the flower. The hypanthium helps in many ways with the reproduction and cross pollination pathways of most plants. It provides weather protection and a medium to sustain the lost pollen, increasing the probability of fertility and cross-pollination. [6]
Under each microsporophyll is one or several microsporangia (pollen sacs). The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which when fertilized by pollen become seeds. The female cone structure varies more markedly between the different conifer families and is often crucial for the identification of many species of ...
Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are positioned so that the pollen can land on the flower's stigma. This pollination does not require an investment from the plant to provide nectar and pollen as food for pollinators. [6] Some flowers produce diaspores without fertilization ...
The pollen is carried to the pistil of another flower, by wind or animal pollinators, and deposited on the stigma. As the pollen grain germinates, the tube cell produces the pollen tube, which elongates and extends down the long style of the carpel and into the ovary, where its sperm cells are released in the megagametophyte.
Self-pollination occurs when pollen from one flower pollinates the same flower or other flowers of the same individual. [45] It is thought to have evolved under conditions when pollinators were not reliable vectors for pollen transport, and is most often seen in short-lived annual species and plants that colonize new locations. [ 46 ]