Prints: Studying the Fungi

Transcription

1 Spore Prints: Studying the Fungi Grade Level 5-12 Figure 1 The visualization of mushroom parts, measurements required with Applied Vision software, and understanding of spores can be easily done at grades More advanced students could be required to stretch beyond the basics of this exercise and elucidate the asexual-sexual cycle, requirements for growth, produce more sophisticated dissections, and do comparisons of different speciess of mushrooms. If using this as a demonstration for the class, have the students view the mushroom on their tablet with EduCam Classroom Viewer. They can capture and label the image to save for their collection of data and presentations as you demonstrate live with a digital stereoscope. Objectives 1. The student will observe and collect data from the spore print. 2. The student will use the metric system to take measurements and calculate averages. 3. The student will employ simple equipment and tools to gather data. 4. The student will demonstrate the use of 21 st century technology with a document camera. National Standards NS Science as Inquiry NS NS NT.K-12.1 NT.K-12.3 NT.K-12.6 Life Science Science & Technology Basic Operations and Concepts Technology Productivity Tools Technology Problem-Solving & Decision-Making Tools 1

2 Background Information In this experiment, you will measure, photograph, and label the different parts of a club fungus, or mushroom. You will take snapshots at various magnifications to identify reproductive spores. Mushrooms are the fruiting bodies of certain types of fungi. Since mushrooms are fungi and not plants, they do not produce seeds during reproduction. The fungi include not only the mushrooms, but the molds, mildews, rusts, smuts, and yeasts, and are considered a taxonomic Kingdom of their own. The actual organism thatt produces the mushrooms is called a mycelium. The mycelium is composed of hyphae, which are usually linked chains of fungal cells and they reproduce asexually. The mycelium is hidden in the rotting wood the mushroom is on, or within the soil. The mycelium produces enzymes which digest organic matter. This digested material is then absorbed by the hyphae (passive diffusion) through their cell walls. The mycelium can be microscopic or fill acres. Overtime the mycelium will create new hyphae whichh branch out and become new mushrooms. Within the cap of the mushroom, on the gills there are basidia, each of which will produce tiny reproductive packets called spores. The number of spores varies with each species of mushroom. The basidia are part of the gill surface and are attached to the hyphae which underlay them making up most of the gill tissue. The basidia are the source of the spores and line the gill surface. Spores are produced by sexual reproduction. The highh degree of gill folding increases the surface area, therefore allowing for more basidia and therefore allowing for thousands of spores to be produced. The spores are released from the basidia by complex means and the spores can land far from the parent fungus by being carried on the wind or by animals. When the spores land somewhere that favors the growth of fungi, usually a moist and shady area, they begin to grow into the threadlike structures called hyphae. These hyphae threads can pack tightly together under the surface of the soil to form a matted structure called a mycelium, which completes the life cycle and which makes up most of a fungus s body. The 2

3 reproductive cycle normally has an asexual phase, mycelium and hyphae, and a sexual phase, basidia and spores, though this varies among fungal species. MATERIALS Digital Stereomicroscope Metric Ruler Pipettes Scalpel Forceps Water Glass Beaker White Sheet of Paper Mushrooms suggest Agariucus bisporus or similar domestic mushrooms; white button, Portobello, cremini, swiss brown mushrooms. SAFETY Use care when handling glass microscope slides, glass cover slips, and scalpel. They break easily and can cause cuts and abrasions to the skin even if not broken. DISPOSE OF SLIDES PROPERLY. PROCEDURE Activity 1 Calibrating the Digital Stereoscope 1. Connect the digital stereoscope in the USB port of the computer. 2. Once connected, launch Applied Vision software on the computer. A live camera view should appear. 3. Within the field of view of the microscope, place the metric ruler showing millimeters. 4. On the lower menu, select Take a Snapshot & Annotate. 5. A new window will appear and it will be labeled Image. 6. Select the second tab, Measure. 7. Measure a denoted length on the ruler, for example, 10mm. 8. To measure, hold down the mouse button and drag the line across until you have measured a specified length then release the mouse button. 9. The line should appear orange if measured correctly. 10. In the lower menu, select Calibration and a New Scale window appears on the screen. 3

4 11. Name your new scale, the known distance, and what units you are measuring in. For example, Stereoscope 4x, 10, mm 12. When you are finished, save the scale, select OK. 13. To make sure your scale is saved, in the lower menu select Select/Remove Scale and then select Select Saved Scales. The new scale you created should have a checkmark by it denoting that it is the scale in use. 14. Place a new object underneath your camera or microscope and repeat steps 4-8. If using this as a demonstration for the class, have the students view the ruler/specimen on their tablet with EduCam Classroom Viewer. They can capture and label the image to save for their collection of data and presentations. Activity 2 Spore Prints Note: I suggest using mature portabella mushrooms for this activity. Gilled mushrooms have basidia located on the gills on the underside of the cap. It is best to use a mature mushroom m because the spores are dropped from the gills when the mushroom is mature. A mushroom is mature when it has a well defined Annulus ring (see Figure 1). 1. Take a white piece of paper and a glass beaker. This works best with 7-9 cm portabella mushrooms. DO NOT WASH the mushroom. 2. Pick a mushroom that has dark visible gills that are not damaged. 3. Carefully cut the mushroom stem off just below the cap, so that it will lay flat with the gill side down. Be careful not to abuse the lower cap area of the mushroom. 4. Place the mushroom cap gill glass beaker. 5. Leave it covered and undisturbed for 24 hours. side down on a white sheet of paper and cover the cap with a 6. At least 24 hours later, carefully remove the beaker and the mushroom cap from the paper, and on the paper you will seee a spore print. 7. Take the spore print paper and place it under the digital stereoscope and take images at all magnifications. (i.e. 4x and 8x on my digital stereoscope) 8. Using one of the images taken, measure 10 individual spores and calculate an average diameter of a mushroom spore from this species of mushroom. a. What previously calibrated unit did you use to measure the spores? (µm, mm, cm) 4

5 b. Average (µm, mm, cm) Spore 1 2 Measurement Analyze and Conclude 1. Were you able to view any spores at the lower magnification? If no, why? 2. If so, describe the shape of the spores that you saw. 3. If not, were the spores easier to see at the higher magnification? What did they look like? 4. What techniques would you use to go about looking at the mushroom hyphae? Where are the hyphae located and what is their function? Extension Examine different types of mushrooms from the local supermarket to observe different types of edible mushrooms. Examine each type for spores, both grossly and microscopically. Preparee images and match them with the data collected to illustrate between species of club fungi. Research for images and information to compare edible mushroom samples to non- between edible or poisonous mushroom samples. Compare the structural differences the two and create image representative samples. Prepare a presentation or panel to compare edible vs. poisonous mushroom anatomy and point out the important structural difference. 5