10.2 Pollination

Spruce tree releasing a large volume of pollen into the air.

A Spruce tree releases a large volume of pollen that is carried by the wind. Common wind pollinated plants are corn, ragweed, and trees such as maple, birch, willow, and elm.

Close up photo of an apple blossom showing the anthers and pistel.

Cross pollination occurs when pollen from a flower (in this case an apple blossom) is transferred from the anther (in yellow at the top of each stamen) of one blossom to the stigma (green) of another plant.

Elegance of Pollination

Beehive with an orchard of apple trees in the background.

This stretches the capacity of migratory beekeepers as they move fewer colonies all over the country in an effort to pollinate all the food crops that require insects to do the work of transferring pollen from one blossom to another.

Honey Bee Health and the Future of Pollination

If the honey bee population drops too low, it will not only likely jeopardize human food supplies around the world, but also reduce the wide variety of fruits and vegetables in the human diet. Some farmers and entrepreneurs are trying to cultivate larger populations of other species of insect pollinators, like bumble bees and blue orchard bees in an effort to capitalize on the niche left by the declining honey bee, but it is unclear which practices will prove to be sustainable.

Honey bee health has impacts beyond agriculture because bees pollinate all kinds of flowering plants that are integral parts of the complex food web and ecosystem of our planet. Halting the decline of the honey bee population is a better approach than finding substitutes that can do their jobs. This may require changes in human behavior and honey bee management practices so scientists continue to study and explore the life and world of the honey bee in an effort to bring helpful new (or old) ideas to light.

Pollination Troubles

Since pollination is dependent on many factors, there are times when it doesn't happen or doesn't happen enough.

Some species of plants, like melons and cucumbers, have male and female flowers and they may not always open at the same times. Plants may grow in places where pollinators can't get to them, like on a high balcony of a tall building or in a non-native location. Maybe only a few pollinators stop by at the appropriate time due to weather.

Whatever the causes, if a plant is not pollinated, the fruit of that plant will not grow. If it is partially pollinated, it will grow, but it will look small, possibly misshapen, and could be a different color than a well-pollinated example.

Aside from hand-pollinating every flower, the best way to ensure thorough pollination is simply to have lots of pollinating insects around!

Photo of partially pollinatd cucumber versus completely pollinated cucumber. Partially pollinated cucumer does not have seeds in nearly half of the cucumber and the fruit does not grow well around that portion.

A partially pollinated cucumber (left) compared to a completely pollinated cucumber (right). The seeds did not form throughout the poorly pollinated cucumber and consequently the fruit did not grow around that portion.

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