Episode 333: Pollen

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Transcript 5/25/24:

There is life all around us—breathe it in! Welcome to The Nature of Phenology where we share the cycles and seasons of the outdoors. I’m your host, Hazel Stark.

There are many clues in nature that tell us what was there before. There are the obvious signs, like animal tracks and scat, indicating what animal passed through. Then there are the more subtle and often hidden clues, like stone walls and foundation holes or lilacs and rhubarb in the middle of the forest indicating human tending in that spot once upon a time. In the spring after the waterways have begun to drop, I love exploring rivers and noticing how high the moving ice of winter scraped the banks or the tree trunks nearby. After all the flooding of this past winter, seeing clumps of mud and grasses high up on a tree branch next to a river is a stark reminder of just how high the water got. But this time of year, if runny noses and itchy eyes aren’t a clear enough clue, evaporating puddles and the surfaces of vehicles reveal a yellow line of scum or dust that indicates just how many plants are flowering and releasing pollen.

Pollen is often treated as a nuisance—the cause of seasonal allergies or hay fever. But where would we be without it? If you survive by eating plants or eating something else that eats plants, you need pollen. Plants produce this fine, powdery stuff to aid in reproduction. The grains are produced in the stamens of a flower, the tubes that typically surround the center of a flower capped with a wider and thicker spot where the pollen sits, called an anther. The goal is for that pollen to make it to another flower of the same species and land in the pistil—the female part of the flower that is in the center. This combination of male gametes from the pollen of one flower with the female gametophyte in the pistil of another creates a seed that ideally contains the best genetics of both parent plants so that the next generation is even better adapted to survival than the last.

While bees get most of the credit for being pollinators—those responsible for moving that substance from one flower to the next—there are so many forms of pollination. Yes, insects like bees, butterflies, moths, ants, and even beetles serve as pollinators, but so do animals like bats and hummingbirds. These animals are typically not after the pollen itself; rather, they are interested in consuming the sweet nectar within the flower and end up moving pollen around as a result.

The plants that rely on animals for their pollination services often produce sticky pollen that easily adheres to the bodies of those visitors. But other plants rely on wind or even water for pollination to occur. Our local firs, spruces, and pines all rely on wind to blow it from their male cones to their female cones. Grasses, wheat, corn, barley, and oats, as well as oak trees, birches, poplars, and maples are also wind-pollinated. The pollen grains of these plants are typically smooth and light so that a breeze can easily pick them up and carry them away. So these wind-pollinated plants are the usual suspects for causing seasonal allergies because their pollen readily drifts in the air we breathe.

Unfortunately, if you are someone who suffers from seasonal allergies, scientists are realizing that climate change is both increasing the length of pollen seasons and the concentration of pollen produced, so allergy season is getting longer. But knowing what plant’s reproductive dust irritates you the most can help. This is yet another great use of a phenology journal—not only noting what plants are flowering, but what noses in your family are running when so you can take some preventative steps to make allergy season a bit more comfortable. Many wind-pollinated plants have fairly inconspicuous flowers, though, so a resource like Pollen.com provides maps that indicate what plants are blowing that sometimes irritating powder around at a given time can help.

Often, we don’t see pollen unless we’re really looking closely at a flower, but this time of year, so many wind-pollinated plants are blowing theirs around that we may see concentrations of this yellow stuff building up on surfaces around us. So the next time you’re outside, you could be a nature detective and try to find some pollen and figure out where in a given plant it’s being produced.

You can find a link to the transcript, photos, information about podcasting and more by visiting archives.weru.org. Thanks for listening and please join us next week for another dive into The Nature of Phenology.

References:

Anderegg, W. R. L., Abatzoglou, J. T., Anderegg, L. D. L., Bielory, L., Kinney, P. L., & Ziska, L. (2021). Anthropogenic climate change is worsening North American pollen seasons. Proceedings of the National Academy of Sciences, 118(7). https://doi.org/10.1073/pnas.2013284118

What in the World Is a Pollen Allergy? (2015, July 13). http://Www.pollen.com. https://www.pollen.com/allergy/pollen-allergy