Fungi chapter 36
Mycology=the study of fungi
- Heterotrophic
secrete enzymes and absorb food
- Filamentous
bodies
- Reproduce
sexually with nuclear exchange(no gametes)
- Cell
walls of chitin & sugars (like that of a crab shell), not cellulose
- Mitosis
takes place in the nucleus only (spindles form there)
Body of fungi
- Hyphae=cells
joined end to end
- Septa=separations
in the cell wall separating cells allowing cytoplasm to stream from cell
to cell
- Mycelium=groups
of hyphae
Reproduction
- Sexual
and asexual reproduction is possible in fungi
- Mycelium
contain haploid nuclei
- After
fusion in two of the three types of fungi haploid nuclei remain separate
in cytoplasm
- Hyphae
that develop can be of
- Heterokaryotic: hyphae with nuclei from two
genetically different individuals
- Homokaryotic: hyphae with genetically identical
nuclei
- Dikaryotic: hyphae with two distinct nuclei
within each compartment
- Monokaryotic: hyphae with only a single nuclei
within each compartment
- Classification
based upon reproductive structures:
- Zygomycota:
- Reproduce: fusion of hyphae leads to a zygote
which divides by meiosis during germination.
- Examples:
bread mold
- Imperfect
fungi:
- Reproduce: asexually but parasexuallity occurs
where genes are combined between two genetically distinct nuclei.
- Examples: penicillium
- Ascomycota:
- Reproduce: sexually reproduce. Diploid zygotic nucleus is formed in
ascus of ascocarp. Asexually
resproduce. Commonest by means
of conidia which are at ends of conidiaphores (specialized hyphae).
- Examples: morels, molds, plant pathogens,
yeasts, truffels
- Basidiomycota
- Reproduce: basidoicarp (mushroom) produces
basidiospores (meiosis) of a specific strain. Hyphae of two different strains fuse (fusion of +&-)
produces a secondary mycelium that will produce its own basidiocarp
(mushroom).
- Hyphae
are heterokaryotic/dikaryotic.
- Examples: mushroom, toadstools, puffballs,
rusts
Lichen
- Symbiotic
relationship between fungus and a photosynthetic partner ie. Algae or
cyanobacteria
- Durable,
harsh conditions
Mycorrhizae
- Symbiotic
relationship between fungus and roots
- Fungi increase
surface area for absorption of phosphorus, zinc, copper,
- Plant provides
organic carbon to fungi
- Two types
- Endomycorrhizae: fungal hyphae penitrate roots
- Ectomycorrhizae: surround but don’t penitrate root