Redbuds, dogwoods, cherry trees, azaleas, and many other flowering plants are coloring the landscape and while heralding the beginning of spring. With its beauty, spring brings about the pollen season.
Recently the pollen levels have been at record highs causing misery to many people. It can cause allergic reactions with symptoms such as itchy eyes, sneezing and other respiratory difficulties. Many who do not normally have allergic reactions are suffering due to the high pollen counts.
In spite of the problems it causes, pollen plays an important role in the reproductive processes of plants.
Pollen consists of tiny grains that are produced in the male parts of flowering and cone-bearing plants. It is transferred to the female parts of the flowers, resulting in fertilization and the production of seeds. There are basically two kinds of pollen. Some plants, mostly ones with showy flowers, produce pollen with a sticky substance that is spread to other plants by insects such as honeybees. It is not dispersed through the air and seldom causes allergic reactions. The other type is pollen dispersed by the wind which is the source of most of the problems. Most plants without showy flowers produce lightweight pollen grains. They shed their pollen into the air on warm, dry days, releasing large quantities to improve the likelihood of pollinating the female flowers.
Pine trees are an example of wind-pollinated plants. They produce vast amounts of pollen that can cover everything. The individual grains have two large wings that help disperse it through the air. Often large clouds can be observed being blown by the wind. The amount produced and released depends upon relative humidity, wind, and the overall health of the male pine cone. The yellow pollen from pine trees often gets blamed for the allergies. However, it is not a potent allergen and the individual grains are too large to penetrate deeply into the respiratory tract. The real culprits are the various weeds, grasses, and trees such as oaks, birch, and hickory. Their pollen grains are much smaller and have chemicals that can cause allergic reactions.
Not much can be done to prevent pine pollen from falling on everything. Just wash it off or sweep it away. For the smaller grained pollen that causes allergies, there are a few tactics that can reduce their effects. Limit outdoor activities during periods when the concentration is high. Weather reports on local TV news stations give information on the pollen count so you can plan your day around it. If you must work outdoors, wear a dust mask to help reduce the inhalation of pollen. To keep it out of your home, keep the windows and doors shut and use a hypoallergenic air conditioning filter. Rain can remove it from the air and wash it away. The pollen counts are usually much lower after a rainfall. If allergies are serious, consult a physician.
As you can see, pollen is a necessary part of plant reproduction. The pollen grain is a container for DNA. This is the means by which genetic diversity is maintained by plants. Even though pollen causes difficulties for some people, we need to appreciate the important role it plays in nature.
Timothy Daly is an Agriculture and Natural Resources Agent with Gwinnett County Cooperative Extension. He can be reached at 678-377-4010 or Timothy.firstname.lastname@example.org.