Activity 5-1 Additional Teacher Tips
Pollen and Spore collection
Teacher Notes
Prior to the students doing Activity 5-1 (Pollen Examination: Matching a Suspect to a
Crime Scene), the teacher should prepare a pollen collection. Pollen can be collected
inexpensively from a variety of sources and stored for use at a later time.
Materials for Teacher’s Pollen Collection
Various pollen samples
Microtubes
Microscope, preferably digital (optional)
Access to a computer with Excel (optional)
A drying tray (or surface)
Forceps
Microscope slides and cover slips
Beaker of water with dropper
Clear nail polish (if you wish to make permanent slides)
Basic procedure:
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Collect and photograph the flowers (or pine cones for pollen).
Collect and photograph fungi (if you are examining spores).
Record the data about the flowers, pinecones, or fungi in the data tables.
Collect pollen and/or spores and store in individual labeled microtubes.
Prepare wet mount or permanent slides of the pollen and spore samples.
Measure the size of each pollen grain or spore.
Photograph the pollen or spore under the microscope.
Record data about pollen and/or spores in the data tables.
Prepare microtubes containing four different types of pollen. Label them as
Suspect 1
Suspect 2
Suspect 3
Suspect 4
Select one of your suspects, 1–4, to be the perpetrator.
Prepare a microtube of pollen labeled Crime Scene (this pollen should match
the pollen of one of your suspects).
Teacher Tips:
A. Free and inexpensive sources of pollen and spores
Visit a local florist, floral department (grocery store), or garden, and collect various
flowers to use as your pollen source. If you know a funeral director, they might be
able to supply you with some older flowers that still have pollen. Keep flowers in
separate paper bags to prevent mold formation and confusion of pollen sources.
If you want a supply of flower pollen ready to use at any time of the year, visit a
Chinese grocery store and purchase a bag of dehydrated lily flowers. These are used
to prepare Chinese dishes such as moo shu pork. When you want to do this lab, you
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first must soak a handful of dehydrated lily flowers in tap water for at least one
hour. Students can dissect the flower and identify all floral parts. Pollen can be
obtained by touching the anthers of the lily flower.
Pollen can also be collected from male pollen cones. These are the small, nonwoody cones that appear in clusters on gymnosperm trees such as evergreens. These
are only produced during the spring. Samples can be collected and stored for later
use.
Spores can be easily collected from mushrooms or puffballs. (Note that only mature
puffballs, usually brown in color, will release mature spores.) To obtain spores from
a mature mushroom (one that has exposed gills), simply place the mushroom cap on
a sheet of paper so that the gills are in contact with the paper. The spores will be
released from the gills and should be air-dried for several days. (Keep this in an
area, such as a covered shoebox, where it can’t get contaminated with other
particles in the air.) After the spores are dried, they can be stored in microtubes for
later use.
B. Collecting and storing pollen and spores
It’s a good idea to collect and preserve pollen and spores throughout the year. Many fungi and
flowers bloom at specific times of the year that may not be available when you want to do the
lab. The presence of a particular type of pollen or spore may help determine when a crime
occurred. Excellent sources of pollen include lilies, impatiens, tulips, gladiolas, alyssum,
rhododendrons, and portulaca. Sources for spores include field mushrooms and puffballs.
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1. Using forceps, remove the anthers of the flowers, making sure to thoroughly clean
the forceps between flower types.
2. Place the anthers (and pollen) in a labeled micropipette tube, leaving the tube open to
the air. Collect all pollen samples in a similar manner. Let the anthers air-dry for
several days before closing the cap on the microtube. (This is your reference
collection.)
3. When collecting spores from fungi, be sure that the fungi you select is mature. When
using a mushroom, the gills under the cap should be visible. Puffballs usually turn
brown when they are ready to release spores.
To obtain mushroom spores, simply place the cap of the mushroom on a sheet of paper
so that the gills come in contact with the paper. The spores will drop out of the
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mushroom’s gills. If the mushroom is dry, place it in a zip-top bag and shake. Cut a
small hole in the corner of the bag to dispense. You will have enough spores for years.
To obtain spores from a mature puffball, cut open the puffball on a sheet of paper. The
spores will collect on the paper.
Before placing spores in microtubes, allow the spores to air-dry. It’s a good idea to
prepare many microtubes of the same type of pollen or spores. This allows you to
prepare several different lab stations, and it will also provide you with backup
specimens.
C. Preparing a reference slide
4. Make and label a slide of each type of pollen or spore using either water or clear nail polish
(use clear nail polish to make slide permanent slide). Don’t forget to label the slide with the
name of the specimen, color of the specimen, and date you collected the specimen.
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Apply a very thin layer of clear nail polish.
Sprinkle the pollen or spores over the top of the wet nail polish.
Apply a cover slip.
D. Photographing your pollen or spores
5. If a digital microscope is available, photograph each pollen type under 100X and
400X power. Label and measure each sample for later reference (optional).
6. If you do not have a digital microscope, photographs of your pollen and/or spore
samples can easily be taken using a digital camera held over the eyepiece of the
compound microscope. To help concentrate the light, you will need an empty film
canister. Cut off the bottom of the film canister. (You may need to try several types
to find one that fits the lens of your digital camera.)
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Focus the microscope.
Place the cut-off film canister over the eyepiece of your microscope.
Place your digital camera so it fits into the open end of the film canister.
View the image through the screen (or eyepiece) on the camera.
Move the camera slightly until a clear image is visible.
Snap the picture.
7. Another suggestion is to take a photograph of the flower and the pollen from that
same flower. Students could also prepare a pressed sample of the flower.
8. Create your crime scene using one of your pollen samples as a source found on the
suspect and at the crime scene. Students can also test the pollen grains for the
presence of starch granules by using Lugol’s iodine. Since the pollen grains contain
starch, the pollen grains should turn a blue-black color in the presence of Lugol’s
iodine.
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Data Table for Teacher’s Pollen Collection
Name of
Flower
Date and Season
Collected
Date
Season
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Description
of Habitat
Color of Diameter
Flower
of Flower
Pollen
Color
Pollen Size
Length
Width
Sketch of Photo
of Pollen Grain
Pollen
Micro
tube #
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Data Table for Teacher’s Spore Collection
Name of
Fungus
Date and Season
Collected
Date
Season
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Description
of Habitat
Color of Diameter Spore
Fungus of Fungus Color
Spore Size
Length
Sketch of Photo
of Spore
Width
Spore
Micro
tube #
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