Fungi Nonvascular

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FungiNonvascular Seedless Vascular Plants

• Labs 15 16

2
A Fungus is Not a Plant

• Fungi lack chlorophyll no photosynthesis
• They are heterotrophs, secreting digestive
  enzymes and absorbing the organic molecules.
• Fungi have cell walls made of chitin.
• Not cellulose as in plants.

3
The Body of a Fungus

• Fungi exist in the form of slender filaments
  called hyphae.
• A hypha is a long string of cells.
• Walls dividing one cell from another are called
  septa.
• Septa do not form a complete barrier cytoplasm
  can flow between cells.

4
The Body of a Fungus

• The main body of the fungus is a network of
  hyphae that grow through soil or wood.
• Mycelium a mass of hyphae
• Mushrooms are temporary reproductive structures
  of a fungus.

5
The Body of a Fungus

• All parts of the fungus are metabolically active,
  secreting digestive enzymes and attempting to
  digest any organic material that it comes in
  contact with.

6
Reproduction in Fungi

• Spores are a common means of reproduction in
  fungi.
• Small, light spores can remain suspended in the
  air for a long time, aiding dispersal.
• Upon landing, the spore germinates and begins
  forming new hyphae.

7
Obtaining Nutrients

• External digestion digestive enzymes are
  secreted into the surroundings, then organic
  molecules are absorbed back into the fungi.
• Many fungi can break down cellulose into its
  glucose subunits.

8
Ecology of Fungi

• Fungi and bacteria are the principal decomposers
  in the environment, breaking down organic
  materials and returning the components to
  circulation in the ecosystem.
• Fungi are able to break down lignin in wood,
  making C, N, P from a dead tree available to
  other organisms.

9
Phylum Zygomycota

• Zygomycetes The 2 nuclei fuse and form a
  diploid zygote. fungi that make zygotes
• Bread mold
• No septa

10
Phylum Ascomycota

• Ascomycetes largest of the 3 phyla.
• Yeasts
• Morels truffles
• Pathogen causing Dutch elm disease
• Ascomycetes are named for the reproductive
  structure called an ascus.

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Phylum Basidiomycota

• Basidiomycetes contains mushrooms, puffballs,
  shelf fungi, also rusts smuts (important plant
  diseases).
• Zygotes form within a structure called the
  basidium.

12
Yeasts

• Yeasts are unicellular fungi.
• Probably derived from multicellular ancestors.
• Important in making bread, bear, wine.
• Other species are pathogens.

13
Imperfect Fungi

• The 3 Phyla differ mostly in their mode of sexual
  reproduction.
• Many fungi seem to have lost the ability to
  reproduce sexually the imperfect fungi.
• Mostly ascomycetes
• Penicillium
• Antibiotic
• Others give flavor to Camembert Roquefort
  cheeses

14
Fungal Associations

• Fungi sometimes live in close association with
  other organisms.
• Mutualism a type of symbiosis where both
  organisms benefit.
• Often occurs between a heterotroph (fungus) and
  an autotroph (algae or plant).
• Fungus contributes the ability to absorb
  minerals nutrients from the environment.
• The photosynthesizer contributes the ability to
  use sunlight to make food.

15
Lichens

• Lichen a symbiotic association between a fungus
  and green algae or cyanobacteria.
• They are very sensitive to pollutants because
  they readily absorb substances dissolved in rain.

16
Lichens

• Lichens can live in harsh habitats due to the
  durable construction of the fungus and the
  photosynthetic ability of the algae or
  cyanobacteria.
• Lichens are often the first colonists in areas of
  bare rock.

17
Mycorrhizae

• Mycorrhizae an association between a fungus and
  plant roots.

18
Mycorrhizae

• Filaments of the fungus act as superefficient
  root hairs transferring phosphorous other
  minerals from the soil into the roots of the
  plant.
• The plant supplies organic carbon to the
  symbiotic fungus.
• Good example of mutualism.