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Fungi
The Fungi Kingdom contains:
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Molds
Mildews
Rusts & Smuts
Yeasts
Mushrooms
Most fungi are saprophytic or parasitic
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They break down organic material returning nutrients to the soil.
Yeasts are useful in the making of bread and fermented drinks.
Human pathogens e.g. athlete's foot and ringworm.
Fungi Body Parts:
1. Hypha - the vegetative filament.
2. Septum - perforated cross walls.
3. Mycelium - a mat of interwoven hyphae.
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Fungi cell walls are made of chitin.
Plant cell walls are made of cellulose.
Fungus life cycle:
Begins as a spore that grows when conditions are right.
Out of the spore wall grows a hypha.
The body of the fungus is made up of hyphal threads collectively called the mycelium.
The mycelium grows in soil or within dead wood or living organisms.
When growing conditions are favorable, the mycelium develops fruiting bodies, e.g. mushrooms.
Fruiting bodies produce new spores.
Types of reproduction:
Asexual:
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Forming spores at the end of the hyphe.
Fragmentation- If the hyphe are broken, the pieces will grow into complete new
organisms.
Yeasts reproduce by an asexual process called budding. In this process, the yeast
cell pinches itself off to produce a small offspring cell.
Sexual:
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Each of the four divisions of fungi have different forms of sexual reproduction.
Fungi nutrition:
Heterotrophs – Fungi do not contain chlorophyll.
Saprotrophic - Decompose dead matter.
Parasitic - Obtain nutrients from living organisms.
Extracellular digestion by secreting enzymes into environment and absorbing the nutrients
produced.
Fungi store their food as glycogen (like animals). Plants and green algae store their food as
starch.
Fungi Classification, the Divisions (Phyla):
Zygomycota:
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Common bread
mold
Hyphae lack septa
Asexual
reproduction is by
conjugation
Stinkhorn
Basidiomycota:
Mushrooms, puffballs, rusts, smuts, and stinkhorns
Underground hyphae intertwine and grow upward to produce a mushroom.
A "fairy ring" (shown below) is actually a single organism. As the hyphae
expand outward, the mushrooms grow around the outer edge. As long as
the organism survives, the circle of mushrooms will be wider every year.
Truffles
Downey Mildew
Mildew
Ascomycota:
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Mildews, yeasts, and truffles (sac fungi)
The largest group of fungi
Named for the reproductive sacs or Asci that form near the tips of the hyphae.
Ascospores are formed here and released into the air when the ascus ruptures.
These spores germinate to form new hyphae.
Yeast
Yeast (Candida)
Deuteromycota:
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Penicillium, ringworm, and athlete's foot (imperfect fungi)
Sexual reproductive stage has not been observed.
Over 90% of plants have fungi associated with their roots. The fungus absorbs and
concentrates phosphates for delivery to the plant roots. In return, the fungus
receives sugars synthesized by the plant during photosynthesis.
Lichens: a symbiotic association between a fungus and a photosynthetic
partner, usually green algae.
The fungi hyphae provide protection and hold moisture while the
photosynthetic partner provides food.
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Upper Cortex: Short, thick
hyphae pressed together to
form a protective layer.
2. Photosynthetic Layer: In
most lichens, the algae are
found in a single layer under
the protective cortex.
3. Pith: A loosely woven mat of
hyphae holding moisture.
4. Lower Cortex: Just like the
upper cortex protecting the
bottom of the group.
5. Rhizomes: Bundles of hyphae
anchoring the group.
Green color is because of the green algae cells
growing between the hyphae of the fungus.
The grey is a lichen
The orange is a fungus without algae