Students will learn that the air contains numerous microscopic particles include many types of pollen and spores.
The class will expose microscope slides for 24 hours in an outdoor location. A drop of pollen stain will be added and the slide covered with a coverslip. The slide is then ready to be examined using a microscope. The pollen grains will stain bright pinkish-red while fungal spores do not stain. Many spores are yellow, golden, or brown while others are colorless. Students should be able to see many types of pollen and spores and also see that there are more spores in the air than pollen.
Pollen is part of the reproductive cycle in flowering plants and is produced by the male parts of the flower. The female parts of the flower produce ovules. In order for seeds to be produced, the pollen must be transferred from the male part of the flower to the female part of the flower. Pollen is transferred by wind or carried by insects. Insect-pollinated flowers usually have large, showy, and brightly-colored petals, which attract insects. In wind-pollinated plants the flowers are very small and inconspicuous. They produced enormous quantities of lightweight pollen that is readily dispersed by the wind.
During springtime the atmosphere contains many types of tree pollen. In Tulsa this is our most abundant pollen season. This project can also be planned for the start of the school year since late summer and early fall is the time when weed pollen is abundant.
Fungal spores are the reproductive structures of fungi including molds and mushrooms. The spores are always microscopic and can have many different sizes and shapes. The spores of most fungi are dispersed by wind and often occur in the atmosphere at high concentrations. They are more abundant than pollen in the atmosphere. Fungal spores are present from early spring through late fall (and also occur in winter but at lower levels).
The major purpose of this activity is for students to increase their awareness of what is actually in the air. Although the air may look clear there may be many microscopic particles present in the air including large quantities of airborne pollen and spores. These particles may be important in the reproduction of flowers or fungi.