Card Set Information

2014-04-09 11:06:24
fungi tropical rainforest microorganisms
trop rain
fungi, tropical rainforest,
Show Answers:

  1. In lowland rainforest in Sulawesi, how many of the 1250 beetle species feed directly on fungal fruit bodies or on fungal mycelium in wood
  2. What are mycorrhizas
    mutualistic associations between fungi and plant roots
  3. what percentage of vascular rain forest plants regularly form associations with mycorrhizal fungi
  4. According to Kiers et al (2000) why has the mutualism between mycorrhizal fungi and plant roots been formed?
    transport of carbohydrate to the fungus, and mineral nutrients + water to the plant. This improves plant nutrient uptake and drought tolerance, reduces vulnerability to plant pathogens
  5. What is the difference between the two main mycorrhiza types: arbuscular and ectomycorrhizas?
    • Arbuscular: limited ability to degrade organic matter (AM)
    • Ectomycorrhizas- can access nutrients from labile organic material that is otherwise unavailable to plants (EM)
  6. AMs are common and widespread and grow into the root cortex forming what within cortex cells? what are these responsible for?
    highly branched structures (arbuscules) which are responsible for nutrient exchange between host and fungus
  7. EMs are the second most abundant and evolved when
    more recently
  8. what kind of habitats are EMs adapted to on a global scale
    rich in organic material
  9. What select range of species are EMs associated with
    predominantly woody spp (pinaceae, dipterocarpaceae, fagaceae, eucalyptus, fabaceae, nyctaginaceae) incl certain tree families and genera that form monodominant stands
  10. What are additional forms of mycorrhiza and what do they do?
    ericoid mycorrhizas, associated with orchids and Ericaceae. They decompose humic material.
  11. These associations between ericoid mycorrhizas are generally viewed as mutualistic, but what may happen in some cases of orchid mycorrhizas
    they can behave as pathogens and saphrophytes and may gain little from orchids
  12. what plants avoid mycorrhizal associations altogether?
    colonists of open groud (Proteaceae), haustorial parasites (mistletoes), carnivorous species (Drosera, Droseraceae) and those like sedges (Cyperaceae) that live in waterlogged anoxic soils
  13. plants without mycorrhizas usually have what
    finer roots, more root hairs and relatively advance chemical defences
  14. What did Hawksworth and Rossman 1997 estimate to be the number of extant fungal spp globally based on a plant-fungi ratio of 1:6?
  15. However, plant-fungal ratios of around 1:33 have been found in which two studies
    Frohlich and Hyde 1999; Frohlich et al 2000
  16. current estimates of global fungal diversity range from what to what
    0.5mil to 10 mil
  17. Why may the early estimate of 1.5mil be a gross underestimate?
    there were overlooked groups such as lichens and endophytes
  18. plants harbour numerous non-pathogenic fungi called what, in their tissues?
  19. why is the ecological significance of endophytes uncertain
    they appear to have no -ive impacts on plant function, although may provide plants w protection against insects and pathogens
  20. endophytes have been found in how many plants
  21. what suggests that the tropical endophytes may be extremely diverse
    evidence of host preference and spatial heterogeneity
  22. how many endophytes did Aptroot 2001 find n a single Elaeocarpus tree in Papua New Guinea
    200, incl many new spp.
  23. What are 5 mechanisms by which different fungi mediate the process of atmospheric/ biotic nutrient cycling
    • N-fixation: autotrophic/ heterotrophic/ symbiotic. 
    • Trace gas emissions
    • Denitrification
  24. the mechanisms photosynthesis, respiration, and decomposition, carried out by fungi, mediate which key ecosystem process
    carbon cycling
  25. competition for nutrients by fungi contributes to which key ecosystem process
    regulation of primary production
  26. how do fungi affect regulation of secondary consumers
    • pathogenic agents- viruses and bacterial pathogens of insect, birds and reptiles
    • predators- nematode trapping fungi, including wood-rotting basidiomycetes; slime moulds
  27. what mechanisms to fungi carry out to mediate the key ecosystem process of nutrient cycling
    decomposition, nutrient mineralisation; mutualisms for nutrient uptake; leaching losses of N; nutrient immobilisation
  28. decomposition of wood (ligning and cellulose) depends on
    fungi and bacteria
  29. saprophytic fungi incl. diverse range of ___ and ____________ spp
    macro and microscopic
  30. what do the enzymes and acid compounds saprophytic fungi discrete do?
    they degrade large molecular complexes into simple compounds
  31. there is usually a succession of species, ranging from those that colonise fresh material to those that do what
    mop up afterwards
  32. saprotrophic fungi form extensive ____ and networks of aligned _____ that connect and _____ nutrients over several metres (Boddy 1993)
    • cords
    • hyphae 
    • translocate
  33. what do some fungi use these cords as
    raised webs that catch litter before it reaches the ground
  34. in tropical rainforests, these fungal hyphae networks influence what (Guevara and Romero 2004)
    local availability of nutrients
  35. wood decay polypore fungi can also be what
    aggressive pathogens that attack living plants, destroying roots/ cambial tissue and ultimately killing trees/ making them more susceptible to windthrow
  36. what do other polypore fungi do
    colonise trees but dont spread until after tree death
  37. what have studies of Panamanian large wood-decay polypore fungi found
    although the most abundant spp colonise multiple hosts, fungal diversity in this group still exceeds that of the host trees.
  38. the majority of plant pathogens are
    fungi and oomycetes
  39. how do they disperse
    airborne spores
  40. where are they particularly prevalent
    understorey where conditions for germination prevail such as high humidity, surface moisture and cool temperatures
  41. what are the most familiar and what do they cause
    foliar pathgoens- necrosis, chlorosis or leaf deformation
  42. what are damping off diseases
    kill seeds and seedlings
  43. what else can pathogens do
    cause cankers in stems that block plants' vascular systems, decay wood in trunks and roots and also attack flowers and developing fruits
  44. their collective impact on plant performance and survival may be as great as, or even greater than, herbivores. why
    their ubiquity and impact on a no. of life history stages and plant parts
  45. what are the main causes of damping off disease
    Phytophthora, Pythium oomycete spp
  46. what did augspurger 1983 and augsperger and kelly 1984 find on barro colorado island
    That Phytophthora and Pythium oomycete spp infected 80% of examine spp and seedling mortality of Platypodium elegans ranged from 35-81%
  47. once considered fungi, what are oomycetes more closely related to?
    photosynthetic algae such as diatoms and to the malaria parasite
  48. pathology and persistence of Phtyophthora cinnamoni, the best known example, which is a major crop pest, is enhanced by what
    moist conditions
  49. what are also vulnerable to fungal diseases
    seeds in soil bank
  50. According to Hood et al 2004, what percentage annual mortality does Miconia argentea suffer
  51. seed and seedling pathogenic agents are believed to be key players in what
    the density dependent processes that contribute to the maintenance of high species diversity in the tropics.
  52. foliar pathogenic fungi affect many larger plants but are rarely lethal and mainly do what?
    reduce the photosynthetic capacity of leaves
  53. foliar pathogenic fungi are remarkably what
    widespread and abundant
  54. what did barone 1998 find in Panama on 10 tree spp?
    fungal pathogens accounted for 34% of leaf damage
  55. How many out of 21 tree spp examined in several other localities in Panama and Brazil were affected by foliar diseases (Gilber and Sousa 2002)
  56. While foliar pathogens appear ubiquitous across sites and seasons, there is considerable variation in the degree of infection among spp. the probability of infection appears to be related to what
  57. leaf damage caused by herbivores does what
    renders leaves more susceptible to attack by foliar pathogens
  58. Reduction in plant growth due to fungi can be substantial, as in the case of the tree Erythrochiton gymnanthus in Costa Rica, which suffered what reduction in its growth rate due to an infection by the petiolar pathogen Phylloporia chrysita? 
    52% (Esquivel and Carranza 1996)
  59. many tropical forest insects are affect by what fungi
    entomopathogenic fungi
  60. neotropical forest spores may contain as many as _____-_______ spores g-1 of Metarhizium anisopliae which infects various insects including leafcutter ants
  61. the large majority of ants remain uninfected despite the high exposure of leafcutter ants to pathogenic fungi, why is this
    regular self grooming and secretion of antibiotics
  62. fungal spores that germinate and penetrate the host cuticle ultimately kill the insect when the fungus what
  63. entomopathogens often bring about weird behavioural changes in their hosts like dying animals climbing as high as possible, why do they do this?
    so fungal spores spread more widely
  64. What does the Cordyceps genera do once the mycelium has invaded the host
    develop a club shaped organ containing fungal spores which is supported on the end of a stalk which may be as much as 10cm in length
  65. What are the Laboulbeniales?
    minute ascomycetous fungi, obligately associated with arthropods, mostly insects.
  66. One genus of Laboulbeniales is Rickia, which has approx 145 spp. what is the host range?
    encompasses distantly related arthropods such as mites, millipedes, mole crickets, ants and various beetles.
  67. What do the Rickia fungi do?
    attach to arthropod cuticles through which they absorb nutrients, although this appears to have little consequence for the host.
  68. A study in North Sulawesi on Laboulbeniales collected from beetles indicates what? (Weir and Hammond 1997)
    tropical diversity may be high because host species are numerous and parasites appear host specific.
  69. Vega and Dowd 2005 found that fungi are essential to the what of many insects
    digestive processes
  70. What did Suh et al 2005 find when looking at digestive tracts of tropical beetles?
    650 yeasts