Lab Topic 18
Fungal Diversity and Symbiotic Relationships

Lichens and Mycorrhizae

 

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How to study for the practical

Learn the language:
For this topic a vocabulary list is given in your lab manual. You need to know the definitions of the terms. Make flashcards for those that you do not know and work to learn the definitions.

Seek the big picture:
In lab manual a list of Key Concepts and Objectives are given. Be sure that you can explain how the lab addresses or illustrates each.
You will probably find it helpful to outline the background section at the beginning of each lab topic in the manual as it attempts to give you a “big picture” overview.

Apply your knowledge of terms and concepts to reality:
Review the images on this www site for each lab topic in the practical.

You need to develop visual memory so that you can recognize images similar to these in the lab practical questions.

As you look at the images, answer any questions that given with the image. Use you lab notebook and lab manual to check your answers.

Synthesize and consolidate you knowledge:
Draw life cycle diagrams where you can. For each organism, know when mitosis and meiosis occur in the life cycle. Be able to describe the ploidy levels as well as the names of different life cycle stages. If there are special organs involved in sexual or asexual reproduction, know the names, functions and what they look like.

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Body Plan of Fungi

Spores	Mass of hyphae, a mycelium	Example of one type of fruiting body (ascocarp).
Fungi produce spores. What is a spore? Is a spore haploid or diploid?	-An extensive mat of hyphae is called a _______ -The typical body of a fungus is in the shape of long filaments called _________. Hyphae branch and aggregate to form a pattern of interconnecting filaments collectively called _______________.

 Phylum Chytridiomycota

Genus Allomyces representative

Click here to see photos of Allomyces. Use back arrow to return.

What is the phylogentic significance of looking at Allomyces?

How is Allomyces similar to a protist? How to a fungus?

 

Phylum Zygomycota

Rhizopus (breadmold) mycelium growing in Petri plate.  What is the white material growing on the surface of this agar plate?  WHat is the ploidy level of a hypa? What are the dark structures?	Rhizopus zygosporangium (stained)  What is a zygosporangium and why is it important?  Before a zygosporangium can produce spores, what type of cell division must occur?

Rhizopus asexual sporangia at different stages of development What is a sproangium?  What is the difference between a sexual and asexual spore?	Quiet and germinating spores of Rhizopus What is a spore?  What is the ploidy level of a spore?

To what Phylum does this organism belong

Does this organism produce spores in a) asexual reproduction b) sexual reproduction c) both d) neither

In this organism sexual reproduction takes place in the: A. ovary   B. zygospore  C. ascus   D. basidiocarp

T/F Sexual reproduction only occurs in the most ideal climates

How many nuclei are you expecting to observe in each cell?

The spores from two different sporangia shown here are genetically same?

Where are the asexual spores in this organism produced?

Describe the hyphae of this organism A) coenocytic and dikaryotic B) coenocytic with haplid nuclei C) septate with haploid nuclei D) septate with diploid nuclei E) coenocytic with dipoid nuclei F) septate and dikaryotic

In the sexual reproduction of Zygomycota, two types of mating gametangia fuse to produce (A) rhizoids; (B) hyphae; (C) zygospore; (D) asexual spore.

• In each of the above photos, find a mycelium, hypha,  and a zygosporangium.
• If bread is left exposed to air under moist conditions, mold grows on it. Where does the mold come from?

• Every fall in temperate climates, massive amounts of leaves are shed. Using the above photos as a visual, explain the decomposer role of fungi in ecosystems.
  
• Phylum Ascomycota-Sac Fungi

      Molds

Mold on Orange T/F Penicillium, mildew and mold belong to the Phylum Ascomycota. Name one other type of fungus that is also found in this phylum.	Penicillium at 200X (stained) What name is given to these specialized asexual spores?

Powdery Mildew of Lilac

Ascocarp (stained) What is an ascocarp?  What would you expect to find inside an ascocarp? What is the ploidy level of an ascocarp?	High magnification of ascocarp (stained)
Mildew hyphae on leaf surface, Lo mag	Mildew hyphae on leaf surface, Hi mag

• What is function of haustoria? (A) absorb water from soil; (B) produce asexual spores; (C) absorb nutrients from the host leaf; (D) participate sexual reproduction.
• This fungus is a parasite that lives on the leaves of this lilac.  The term that plant pathologists us to denote a fungus that is parasitically associated with the leaves of a plant is ________.
• Describe how a mildew obtains nutrients from its host.
• How do mildews spread from one lilac leaf to another?
• What is the ploidy level of the  hyphae of a mildew?

Cup fungi

You should review the life cycle of Sordaria, an Ascomocota fungus, in Lab Topic 10.

Click here to see photos of whole cup fungi . Use back arrow to return.

Peziza at 400X. Note closely packed asci each containing ascospores (stained). The sac like reproductive structures of this fungus are called____________.  True / False  The spores released by this structure are always formed by meiosis. Which structure below is unique to this organism's phylum? A. basiocarp B. zygospore C. ascus. What is the ploidy level of the spores and hyphae shown here?	How many ascospores are in an ascus?  What type of cell divisions occur in the development of an ascospore?  In cup fungi, a diploid zygote divides to produce 8 ascospores by (A) mitosis and meiosis; (B) mitosis; (C) meiosis; (D) fertilization.. Select the sequence of events that produced the red-stained cells in this slide A) karyogamy-diploid cell-mitosis-meiosis-ascospores B) diploid cell-karyogamy-meiosis-ascospores C) Karyogamy-diploid cell-meiosis-mitosis-ascospores D) Karyogamy-diploid cells-mitosis-ascospores.	Sordaria.  Fungi produce spores. Are they haploid or diploid? What is a spore? What are these spores called? Do they occur during the asexual or sexual phase? What phylum does this organism belong to? Why? Describe what is meant by a "dikaryon" and where this stage fits within the life cycle of an Ascomycete fungus.

Name the structures produced by asexual reproduction in this culture This organism is only diploid at one stage in its life cycle.  Which stage is that? What reproductive structure is featured here? This organism is only diploid at one stage in its life cycle.  Which stage is that? Describe what is meant by a "dikaryon" and where this stage fits within the life cycle of an Ascomycete fungus.

 Phylum Basidiomycota

-Club Fungi

Mushroom (basidiocarp)  showing gills under cap. What division does this fungus belong to?  A. Chytridiomycota; B. Zygomycota;  C. Ascomycota;   D. Basidiomycota. What microscopic structures woudl you expect to find on the gill surfaces? The hyphae in a mushroom are (A) diploid; (B) dikaryotic; (C) monokaryotic. What ploidy level do most of the tissues in this mushroom exhibit?  What is a basidiocarp?	Mushroom cap cross section at low  magnification (stained). On the above photo indicate where you woudl expect to find basidia.
If surface of gill is observed at high magnification basidia are observed.  The structures on this organism that produce the spores are the __________. Each basidium produces how many spores?  Are spores haploid or diploid?  Are basidiospores produced by mitosis or meiosis?	Basidiospores are attached to basidia by small cytoplasmic extensions,

Gills of oyster mushroom.	Bracket fungi This structure was produced from: A) haploid hypae B) dikaryotic hyphae C) diploid hyphae D) none of the above What type of nuclear division gave rise to this structure?
Bracket fungus upper surface	Bracket fungus on left was cut in half to reveal inner structure.

General and Comparative Questions

Define plamogamy and karyogamy. Diagram a general life cycle of a Kingdom Fungi member and show where these two processes occur in the life cycle. Clearly indicate the ploidy levels of the stages.

Define the terms coenocytic and dikaryon.

Compare and contrast the importance of asexual reproduction and sexual reproduction in the Divisions  Ascomycota and Basidiomycota.

What are the distinguishing characteristics of a fungus that are not shared with other organisms?

If you were given a fungus, how would you go about determining if it was a member of one of the four divisions studied in this lab topic?

Compare the life cycles of a fungus in the phylum Ascomycota with one in the phylum Basiodiomycota. How are they similar? How are they different?

Is a fungal spore a seed? Why do you say so?

How are spores from fungi similar to those from seedless plants?

What is the role of spores in the life cycle of fungi?

Compare and contrast the importance of asexual reproduction and sexual reproduction in the phyla  Ascomycota and Basidiomycota

What is the role of fungi in the ecosystem?

What does the cell wall of a fungal hyphae consist of?

List 2 reasons why the fungi group does not belong to the Plant Kingdom.

Fungi have adopted a saprophytic lifestyle.  What is meant by saprophytic?

What are the different types of associations that fungi have with other organisms? Name one example of each.

Why do most plants grow slower in sterile soil (void of bacteria and fungi) than non-sterile soil?

Click here to go to  Fungal Associations

List of related links

Chytrids implicated in amphibian die-offs
Mykoweb: a summary of info about fungi
Tom Volk's Fungus Page at University of Wisconson, LaCrosse
US Forestry Service Site with several good links
British Saccaromyces cerevisiae (yeast) Genetics Research Group at Aberdeen

Credits

Photos by Maria Oehler, Allison Hall , Linda Westagate,  W. D. Dolphin, and Botanical Society of America
Text and layout by W. D. Dolphin