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Spore Dispersal in Fungi Spore D

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					                                          How Do Fungi Get Around?
                                            Although relatively few in species,
                                            fungi are everywhere.
   Spore Dispersal                          The mycelia of some fungi are
                                            potentially able to produce up to
      in Fungi                              “billions and billions” of spores
                                            Not all will give survive, but sheer
                                            numbers ensure some will
                                            Examples from various groups of
                                            fungi.




Ustilago maydis (Corn Smut)              Ganoderma applanatum (Artist Fungus)




                                           Ganoderma applanatum, the Artist
                                           Fungus, perennial fruiting body, 30
                                           billion spores/day and 5.4 trillion
    A gall about 1in3 may contain          spores over a five month period,
    approximately 25 billion               from within the pores of the fruiting
    spores!                                body.




Calvatia gigantea (The Giant Puffball)   Bread Mold, A Microscopic Fungus




  The average size fruiting body of
  this species is approximately 18”         Rhizopus stolonifer, each
  and contains about 7 trillion spores      sporangium contain around
  within.                                   50,000 spores.




                                                                                   1
Blue Mold, A Microscopic Fungus          How Do Fungi Get Around?
                                          Sometimes they don’t!.
                                          Resting spores: Thick walled cells
                                          with food reserve.
                                            Zygospore, enclosed in thick-
                                            walled zygosporangium.
                                                             Zygosporangium

  Penicillium colony 2.5 cm may
  produce 400,000 spores/day.




 How Do Fungi Get Around?                How Do Fungi Get Around?
  Sometimes they don’t!.                  Sometimes they don’t!.
  Resting spores: Thick walled cells      Resting spores: Thick walled cells
  with food reserve.                      with food reserve.
    Teliospore: Thick walled over           Resistant sporangium: Thick
    wintering spore.                        walled cell eventually giving rise
                                            to zoospores.




 How Do Fungi Get Around?                 Wind: Air Borne Spores
  Fungi usually have mechanism by         Most fungi disperse spores by wind.
  which spores are dispersed.                                  dry”
                                          Spores are usually “dry spores and
  A number of mechanisms have             hydrophobic. Why?
                                          hydrophobic
  evolved in fungi to disperse spores:    Most studied group of spores:
    Wind                                    Aerobiology deals with particles
    Water                                   transported in air.
    Insects                                 Fungal spores can cause allergies
    Animals                                 unknown until 1924.
    Active mechanisms                       Mostly caused by common
                                            microscopic fungi = molds




                                                                                 2
Wind: Air Borne Spores                 Wind: Air Borne Spores
Most studied group of spores:          Most studied group of spores.
 Thousands of tons of spores of        Christensen (1975): Demonstrated
 two most common air borne fungi,      effectiveness of air dispersal:
 Cladosporium and Penicillium,            Utilized Cladosporium resinae,
 have been measured.                      as a marker fungus.
 Air samples may contain                  Species known only from resin
 approximately 200,000                    permeated soil or wood
 spores/meter3.                           impregnated with coal tar
 Particles easily suspended in light      creosote, i.e., telephone poles
 beam.                                    and in diesel fuel.




Wind: Air Borne Spores
Christensen (1975): Demonstrated
effectiveness of air dispersal:            4
   Species released in Plant
   Pathology Building at University        3
   of Minnesota. A building with
   four floors and no central air          2
   conditioning.
                                           1


                                               Side View of Building




            Hallway




      Top View of Building              Cladosporium resinae spores
                                        “brushed” into air on 1st floor.




                                                                            3
                                     Wind: Air Borne Spores
   Cladosporium Plate                Christensen (1975): Demonstrated
                                     effectiveness of air dispersal:
                                        In order to grow C. resinae,
                                        special medium with creosote
                                        required.
                                        Creosote medium also
                                        prevented other fungi from
                                        growing.




Wind: Air Borne Spores               Wind: Air Borne Spores
Christensen (1975): Demonstrated
effectiveness of air dispersal:
   In order to ensure that C.
   resinae was not already in the
   air.
     Plates with creosote medium
     exposed in building, and soil
     and wood samples before
     experiment. Why?
                                       Thus, C. resinae not present
                                       in plant material and in soil.




Wind: Air Borne Spores               Wind: Air Borne Spores
                                     Christensen (1975): Demonstrated
                                     effectiveness of air dispersal:
                                        Why select Cladosporium
                                        resinae to be experimental
                                        fungus?




  Thus, C. resinae not present
  in air and experiment sight.




                                                                        4
  Wind: Air Borne Spores                   Wind: Air Borne Spores
 Christensen (1975): Demonstrated         Christensen (1975): Demonstrated
 effectiveness of air dispersal:          effectiveness of air dispersal:
    Experiment was in two parts:             Experiment demonstrates
      Plates exposed from 1st to 4th         ability of air borne spores to
      floor, at 5 minute intervals, in       stay afloat.
      labs and hallway.                      Why select Cladosporium
      Seven sets of plates exposed           resinae to be experimental
      from 1st to 4th floor, at              fungus?
      intervals of 0-5, 5-10, 10-20,
      20-30, 30-60, 60-120 and 120-
      240 minutes.




  Wind: Air Borne Spores                   Wind: Air Borne Spores
 Christensen (1975): Demonstrated
 effectiveness of air dispersal:
    An experiment that you can do:
      Place mature mushroom, in
      box, about 10” high, 36”long.



                                         Intuitively, what do you think will
                                         happen?




  Wind: Air Borne Spores                   Wind: Air Borne Spores
          Mushroom                          Ability of spores to stay afloat,
          placed here                       indoors, is reason why
                                            allergies worst indoors, for
                                            some.
                                            Allergies worst when sweeping
                                            and vacuuming.

Top view of spores on cardboard
box bottom. Some spores stay
afloat and land on opposite end of
box!




                                                                                5
  Wind: Air Borne Spores                Wind: Air Borne Spores
  Mechanism of basidiospore
  release:




Basidium ejects basidiospores and     Lower magnification of
falls between gills to be carried     basidiospores falling between the
away by wind.                         gills.




  Wind: Air Borne Spores                Wind: Air Borne Spores

So if
somebody
sneezes in
another room,
they may as
well be
sneezing right
in your face!
                                      Ascomycota fruiting body with asci
                                      and ascospores.




   Wind: Air Borne Spores           Puffballs With Flexible Peridium

  Ascospores
  disperse when                      Ostiole 
                                                                     Flexible
  pressure                                                       
                                                                     Peridium
  within ascus
  “shoots”
  spores
  through
  operculum                          Lycoperdon perlatum: Has flexible peridium
                                     with an apical ostiole where spores are
                                     dispersed when peridium is depressed.




                                                                                  6
Puffballs With Flexible Peridium               Puffballs With Flexible Peridium


                            Outer
                           Peridium
                          
                            Inner
                            Peridium with
                            ostiole
 Geastrum tripex (Earthstar): Has flexible
 inner peridium with an apical ostiole and a
 thick, tough outer peridium that dehisces      Geastrum tripex: dispersing spores
 to form a star-shape.                          following depression of peridium.




Puffball With Thick Rigid Peridium             Puffballs With Rigid Peridium
  Peridium
       



Basidiospores
              




                                                Pisolithus tinctorius: Dispersal of
  Scleroderma levae: Peridium must              basidiospores after disintegration
 dehisce for basidiospores dispersal.           of peridium.




      Peridium Dehiscent                         How Far and How High?
                                                  Some spores believed to
                                                 disperse species world wide.
                   Battarraea steveni:
                   Peridium has a                 Some spores have been found
                   circumscision                  as high as 36,000-71,000 feet.
                   dehiscence. Entire             So what!
                   top portion of the
                   peridium removed
                   when basidiospores
                   dispersed.




                                                                                      7
 Water Dispersed Spores                     Water Dispersed Spores
   Water dispersed spores are
   hydrophillic. They readily absorb
   water.
   Spores are usually also borne in
   slime and are carried away in
   mass, passively.
      Some spores have long
      appendages or are coiled.
      Shapes give high surface
      tension to stay afloat. Air also
      may be trapped.




  Water Dispersed Spores                    Water Dispersed Spores
                                             Zoospores chemotactic:
                                             Movement towards chemical
                                             stimulus.
                                               Stimulus normally towards food
                                               source.



 Zoospores have flagella, can swim,
 but is this important?




     Insect (Fly) Dispersal                 Insect (Fly) Dispersal




Aeroe rubra: A species of stinkhorn.
Foul odor attracts flies. Spores, in
slime eaten and/or adhere to their       Phallus rubicundus, another stinkhorn.
bodies.




                                                                                  8
   Insect (Fly) Dispersal                Mimicry (Pseudoflowers)




                                         Puccinia monoica, plant pathogen
Dictyophora cinnabarina, yet another     induces pseudoflower formation.
stinkhorn.




                                          Mimicry (Pseudoflowers)
 Mimicry (Pseudoflowers)
                                                               Yellow
                                                               pseudoflowers,
                                                               mimic flowers and
                                                               attract
                                                               pollinators.
                                                               Pollinator
                                                               facilitates sexual
                                                               reproduction in
                                                               fungus.
 Puccinia monoica, plant pathogen
 induces pseudoflower formation.




Bird’s Nest Fungi Dispersal             Bird’s Nest Fungi Dispersal
    Common name from its
                                       Peridioles (eggs)
    resemblance to a bird’s nest.
                                              


                                                           

                                              
                                            Peridium
                                       Peridiole contains         Cyathus pallidus
                                       basidiospores and is the
                                       unit that is dispersed




                                                                                     9
Bird’s Nest Structure             Bird’s Nest Structure




                                              




Bird’s Nest Structure
                                    Peridiole Dispersal


                                      Rain drop    Rain drop
                                                        
                                               




 Peridiole Dispersal                Peridiole Dispersal



    Peridiole
                                               
           




           Funicular cord wraps   Funicular cord wraps
           around nearby plant.   completely around substrate.




                                                                 10
Bird’s Nest Fungi Dispersal             Animal Dispersal
   Once attached, peridiole can       Some puffballs are buried
   grow on attached substrate.        underground and do not have an
                                      obvious mechanism for
   Also may be consumed by
                                      dispersal.
   foraging animals.
                                      These fungi are typically dug up
     Peridiole passes through
                                      by animals and taken elsewhere
     animal’s digestive system
                                      to be eaten and later dispersed
     unharmed.




     Animal Dispersal                  Animal Dispersal




Rhizopogon: An example of a        Tuber sp.: The “Truffle” is probably
common puffball that is probably   the most famous example of a
dispersed by foraging animals.     fungus that is animal dispersed.




                                                                          11

				
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