Fungal Diversity Flashcards

1
Q

Role of hyphae

A
  • absorb small molecules directly
  • secrete extracellular enzymes to break down large molecules for absorption
  • ramify over and within the substratum (their food source)
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2
Q

How are hyphae adapted for nutrient absorption

A
  • long
  • thin
  • large surface area
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3
Q

Mycelia

A

Diverging hyphae with tangential connections to form networks
(Occurs after isotropic growth phase)
Branching density and network typology largely controlled by nutritional and environmental conditions

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4
Q

How do hyphae grow

A
  • apical growth (from the tips)
  • form walls first and septum later on
  • grow radially and diverge
  • early life they cross over = competition
  • later on they no longer cross = better efficiency in finding nutrients
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5
Q

Name the 6 main hyphae tissues/organs

A
Sclerotia
Pseudosclerotia 
Pseudosclerotial plates
Pseudorhizas
Coremia/synemata
Stromata
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6
Q

Describe sclerotia

A
  • Asexually reproduce
    • Can survive relatively long periods of time in a dormant state
    • Are a mass of densely packed hyphae and then differentiate into solid tissue surrounded by ‘rind’
    • The outer skin protects the internal hyphal mass from drying out.
    • Useful for when fungi goes through tough conditions. When conditions improve it can produce new mycelium or fruiting bodies.
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7
Q

Describe pseudosclerotia

A
  • Heterogenous mix of hyphae and substrate material.
    • Will surround a large volume of substrate, wood or soil with dense hyphal strands/sheaths and turn the mass into fungal biomass and residual substrate = wood inside protected against decay by other micro orgs and serves as food reserve.
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8
Q

Describe pseudosclerotial plates

A
  • Colouration of wood caused by fungi

The point where wood colonies interact and meet each other causes the lines

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9
Q

Describe pseudorhizas

A
  • A tap-root like extension at the base of a mushroom stem

- The mycelium aggregates into sub-cylindrical columns which then bears a fruit body

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10
Q

Describe stromata

A
  • Compact hyphal matrices, in or on which fruit bodies are formed.
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11
Q

Describe rhizomorphs

A
  • hyphal bundles
    • Vary in growth : sometimes grow in regimented way and Sometimes they have founder hyphae that grow first and then other hyphae follow same route and twist around.
    • Are exploratory structures to find nutrients/water in the soil: They also grow quicker than hyphae speeding up the exploration process.
    • Rhizomorphs made of multiple hyphae so when wood found it can fan out and cover the wood more quickly.
    • Can transport large amounts of water, nutrients and oxygen to fungi quickly
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12
Q

What happens when separated hyphae are next to each other

A
  • if the same individual they will fuse back together

- if not the same they will fuse temporarily and then recognise they aren’t the same and separate again

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13
Q

What do fungi feed on?

A

-fixed carbon in plants and materials

Don’t have chlorophyll and cant photosynthesise

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14
Q

Saphrotroph

A

Organism that feeds on and derives nourishment from decaying matter

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15
Q

What are the roles of saphrotrophs

A
  • Nutrient recycling
  • Nutrient translocation
  • Humus formation (humus = dark, organic material that forms when plant/animal matter decays)
  • Soil structure and stability
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16
Q

What are the different types of wood decay caused by saprotrphy

A

Stain
Brown rot
White rot
Soft rot

17
Q

Describe brown rot

A
  • single compounds of cellulose and hemicellulose used
  • lignin isn’t used which causes brown crumbly appearance
  • hyphae lie on cell wall in lumen
  • enzymes (H2O2) diffuse into wall
18
Q

Describe white rot

A

-utilises all compounds including lignin giving it a white fibrous appearance
-hyphae lie on cell wall in lumen
- forms erosion grooves which coalesce
Can completely decompose wood to CO2 and H2O

19
Q

Describe soft rot

A
  • cellulose and hemicellulose used
  • lignin removal absent or slow/incomplete
  • wood cell wall breakdown in immediate vicinity of hyphae
  • type 1 = in S2 layer producing cavities
  • type 2= in lumen giving erosion grooves
  • decay slower and less extensive
  • important in wet and fluctuating moisture conditions
20
Q

Necrotrophic

A

Describing a parasite that kills its host and feeds on the dead matter

21
Q

Biotrophs

A

Parasite that completes its life cycle depending on the living host cells

22
Q

What are the 3 main types of biotrophs

A

Parasites
Lichens
Mycorrhizae

23
Q

How do necrotrophs kill plants

A
  • kill by enzymes ‘damping off’
  • toxins (discrete, spread slowly)
  • Vascular wilts (blocks vascular bundles)