Exam 29: Fungi

Use the following information when answering the corresponding questions). There is much discussion in the media about protecting biodiversity, but does it really matter? Canadian and Swiss researcher to know if the diversity of arbuscular mycorrhizal fungi AMF) was important to the productivity of grasslands M.G.A. van d Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf- Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrh fungal diversity determines plant biodiversity, ecosystem variability and productivity. Nature 396:69- 72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species, no AMF, or all four AMF species together; and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present. Use the graphs in Figure 31.4 to answer the questions that follow. Note that the x- axis labels indicate the number and identity of AMF species bar 0 = no fungi; bars A- D = individual AMF species; bar A+B+C+D = all AMF species together). The y- axis indicates the amount grams) of plant biomass for the species shown in italics above each graph. Figure 29.4 -Based on the graphs shown above, which of the following plant species is most likely not to form mycorrhizal associations?

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

Use the following information when answering the corresponding questions). The researchers then wanted to know if plant biodiversity and productivity would increase in a natural system as a result of i AMF diversity beyond just four species. Consider Figure 29.6 below Figure 2 from van der Heijden et al. 1998): Figure 29.6 -Plant biomass growth) in Figure 29.6 increases as fungal diversity increases. True or false?

It has been hypothesized that fungi and plants have a mutualistic relationship because fungi provide critical nitrogen for the plants' use. How do we know this happens?

Why is it reasonable to hypothesize that lichens might predict air quality?

Use the graphs in Figures 29.4 and 29.5 and the following information when answering the corresponding questions. Canadian and Swiss researchers van der Heijden et al., 1998) interested in factors affecting biodiversity, grew a variety of gra plants in combination with one of four arbuscular mycorrhizal AMF) species, no AMF, or all four AMF species together; and measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF were present. Use the graphs in Figure 31.5 to answer the questions that follow. Note that the x- axis labels indicate the number and identity of AMF species bar 0 = no fungi; bars A- D = individual AMF species; bar A+B+C+D = all AMF species together). The y- axis indicates the amount grams) of plant biomass for the species shown in italics above each graph. Graph e) is the total biomass grams) of all 11 plant species combined; graph f) is the biomass of Bromus erectus plants only, separated from the total. Figure 29.4 Figure 29.5 -What is the major difference between Bromus erectus graph f) and the other plant species graphs a- d) included in the study?

Figure 29.5 -Based on graphs e) and f) in Figure 29.5, which is the most well- supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis?

You are a forester charged with increasing productivity in a South American forest newly planted with pines from Oregon. You believe that the southern forest lacks the fungal diversity needed by the North American pines, and that this lack of fungi is affecting the pines' productivity, but you have no evidence to support your ideas. To count how many fungal species were present in the Oregon forest, which methodology would you choose, and why?

Fungi have an extremely high surface- area- to- volume ratio. What is the advantage of this to an organism that gets most of its nutrition through absorption?

The vegetative nutritionally active) bodies of most fungi are I. composed of hyphae. II. referred to as a mycelium. III. usually underground.

Microsporidians are considered parasitic because of the ability to penetrate their host cells using this structure.

The fungi that we commonly know as mushrooms produce which of the following reproductive structures?

Figure 29.5 -Why does total biomass graph e, Figure 29.5) not vary with AMF diversity?

Use the following information when answering the corresponding questions). Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They w if the same fungal individual would colonize different trees, forming an underground network that potentially could transpor and nutrients from one tree to another S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the fi Nature 388:579- 82). Figure 29.2 illustrates the team's experimental setup. Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years; two of the three species formed ectomycorrhizae Douglas fir, birch) and the other cedar) formed arbuscular mycorrhizae. For the experiment, the researchers placed airtight bags over the Douglas fir and birch seedlings; into each bag, they injected either carbon dioxide made from carbon- 13 or carbon- 14 ¹³CO₂ and ¹⁴CO₂, isotopes of carbon). As the seedlings photosynthesized, the radioactive carbon dioxide was converted into radioactively labelled sugars that could be tracked and measured by the researchers. Figure 29.2 -Referring to Simard et al. 1997), what is the result that would most strongly refute their hypothesis?

Simard et al. 1997) further hypothesized that if reciprocal transfer did occur, it would be a source- sink relationship driven by photosynthetic rates. That is, if one seedling is in full sun and the other in deep shade, there will be a net movement of carbon from the seedling in full sun to the one in deep shade. If a shade was placed over the birch seedlings and the cedar, and the Douglas fir was left in full sun, what result could Simard and colleagues expect?

Figure 29.1 -Looking at Figure 29.1, draw a new graph that plots the percentage of plant species in the fossil pollen and spore record, and write a figure legend comparing it to the original figure.

Based on the idea that fungi have pores between their cell walls, allowing cytoplasm to move from one end of the mycelium to the other, which of the following hypotheses is the most plausible?

Which of the following is an important role for fungi in the carbon cycle?

Use the following information when answering the corresponding questions). There is much discussion in the media about protecting biodiversity, but does it really matter? Canadian and Swiss researcher to know if the diversity of arbuscular mycorrhizal fungi AMF) was important to the productivity of grasslands M.G.A. van d Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf- Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrh fungal diversity determines plant biodiversity, ecosystem variability and productivity. Nature 396:69- 72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species, no AMF, or all four AMF species together; and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present. Use the graphs in Figure 31.4 to answer the questions that follow. Note that the x- axis labels indicate the number and identity of AMF species bar 0 = no fungi; bars A- D = individual AMF species; bar A+B+C+D = all AMF species together). The y- axis indicates the amount grams) of plant biomass for the species shown in italics above each graph. Figure 29.4 -Which of the following best explains the data given in graph b) of Figure 29.4 about Lotus corniculatus?