Pollination

Pollination is the transfer of pollen from the anthers of a flower to the stigma of a flower.  Pollen that is developed in the anthers contain sperm cells. When the pollen reaches the stigma, it forms a pollen tube that grows down through the style toward the ovule that the sperm cells travel through. When the pollen tube reaches the ovule, fertilization between the sperm cell and the egg occurs.  Pollination must take place before fertilization. Fertilization allows the flower to develop seeds.  Some flowers develop seeds through a process called self-pollination. This is when pollen and pistil is used from the same plant that is developing seeds.  Some plants require pollen and pistil from different plants before fertilization can occur, this is called cross-pollination.  Bees, wind, water, and insects are all pollinators that help to move pollen from one flower to another.

 Good pollinators: bees, hummingbirds, moths, butterflies, flies, nectar feeding bats, and wasp. The wind is a good pollinator for plants like corn.

Is pollination important to our survivor? Yes, without pollination the human race would not survive.  Ninety percent of flowering plants rely on pollination. These flowering plants produce the oxygen that we breathe by using carbon dioxide produced by plants and animals. Flowering plants prevent erosion of our stream banks and help purify the water.  Over a thousand crops grown around the world depend on pollination to survive. Some of these crops include: potatoes, bananas, apples, melons, and chocolate.

Since bees are so important for our food production they need to be protected. Destructive farming practices, loss of habitat, and pesticide use are all detrimental to the bee population.  To learn about other dangers to our bee population click here: 

Bee's role in fertilization- when a bee visits a flower it picks up pollen grains from the anther ( the male sex organ). This pollen carries the sperm cells needed to fertilize the female ovule. The bee will carry the pollen grain to another flower where grains of pollen stick to the stigma (female organ). Then the pollen grains grow a pollen tube or root down the pistil to deliver two sperm cells to the embryo seed or female ovule. This tube grows down the length of the stigmatic tissue until it reaches the ovary. Once an unfertilized ovule is found two sperm cells are released. One sperm cell fuses with an egg nucleus to become the seed. The fertilized egg becomes the embryo of a new plant including the body of the plant. The other sperm cell finds the center of the ovule and unites with the polar nuclei where it develops into endosperm to nourish the developing embryo. The endosperm becomes the cotyledons of the new plant.

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Click the picture above to learn more about the parts of a flower and pollination.  

In the United States there are around 4,000 bees. There are around 40,000 bees worldwide. Almost all bees are hairy, they even have hair on their eyes, and this hair transports pollen grains from flower to flower.  Honey bees and bumblebees have indented areas on their back legs that carry the pollen. Pollen is a yellow or green powder like substance that is sticky. Bees are the most important pollinator.  Not only is pollination from bees important to the fruit and vegetable crops it is also an important factor in the supply of beef and milk products.  This is because the alfalfa leefcutting bees pollinate the clover and alfalfa that makes up around one-third of the diet of a cow.

 
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