Transcript Classification of Fungi (II)

ULTRASTRUCTURE
1)
Spores
• Fungi reproduced by means of spores (both sexually
or asexually).
• Moulds, spores germinate to produce branching
filaments called hyphae which may have septa
(divided into cells / crosswalls) or not (coenocytic /
aseptate / non-septate).
• The cells of the hyphae may be uninucleate or
multinucleate. Mass of hyphae is called mycelium.
ULTRASTRUCTURE OF HYPHAE
ULTRASTRUCTURE
1) Spores
• Different types of septum.
• Dolipore septum – found in most complex fungi;
have a central apparatus in the form of a barrelshaped inflation surrounded by a perforated
membrane. This perforated(berlubang) pore is large
enough to permit passage of nuclei and other
organelles.
• In yeasts, a spore germinates to produce round,
oval or elongated single cells that reproduce
mostly by budding (some by fission) and formed
moist or mucoid colonies.
ULTRASTRUCTURE OF SPORES
Dolipore septum
ULTRASTRUCTURE
2) Nucleus
- Nucleus is bounded by a nuclear membrane
and consisting of RNA. (?Euk /?Prok)
- In the cytoplasm : mitochondria, vacuoles,
vesicles, endoplasmic reticulum, ribosomes,
microbodies, microtubules, crystals, glycogen,
golgi / dictyosome).
3) Cell Wall
- The cell wall constitutes of polysaccharides
(chitin, cellulose, glucan, galactose, mannose,
galactoseamine) proteins, lipids.
ULTRASTRUCTURE
4) Mycellium
• Mass of hyphae - called the mycelium.
• Different forms of mycelia - Rhizomorph,
Haustoria, Plectenchyma
• Thick forms of mycelium is called the
rhizomorph which looks like the root tip (has a
thick, hard cortex and a growing tip, resistant
to adverse (buruk) conditions but remain
dormant (x active) until conditions are
favourable, usually produced in complex
fungi such as Basidiomycete).
Mycellium of parasitic fungi grow on the
surface of host plants and called haustoria
which are used to obtain nourishment from
host.
A specialised hyphal invagination of plant
cells.
ULTRASTRUCTURE
4) Mycellium
•
Plectenchyma are mycelium loosely (longar) compact
woven (anyaman) tissues which are different from the
usual loose hyphae and they are of two types:
i.
the prosenchyma (loosely weaved hyphae and
parallel to each other);
ii.
the pseudoparenchyma (closely packed oval
cells).
Both form the stromata and sclerotium.
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Stromata are compact somatic structures which act as
cushion
Sclerotium are hard resting body resistant to
unfavourable conditions and may remain dormant (x
aktif) for a long time until ready to germinate.
GROWTH CONDITIONS
1) Temperature
Most fungi grow best between 0oC to 30oC of
which the optimum temperature range is 20 to
30oC. Thermophilic species can grow to above
50oC or a minimum of 20oC.
2) pH
The pH is pH6.
3) Light
Light is not required but some light is essential for
sporulation in many species. Important role in
spore dispersal (penyebaran).
NUTRITION
1) Saprobe or Parasite
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They are either saprophytic or parasitic.
An Obligate saprobe is incapable of
causing disease on living organisms as they
live on dead organic matter.
A Facultative parasite or Facultative
saprobe can cause disease or live on
dead organic matter depending on
circumstances.
An Obligate parasite must only feed on
living organisms.
NUTRITION
2) Nutrients
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Fungi do not possess chlorophyll and are not
able to make their own food.
But if given carbohydrates (e.g. glucose /
maltose), most of them can make their own
proteins from organic or inorganic sources.
Most fungi need C, O, H, N, P, K, Mg, S, B, Mn,
Cu, Mo, Fe, Zn and Ca (not so for all fungi).
Glucose is the best source for C.
Ammonium compounds and nitrates are the
best sources for N.
Fungi store excess foods in the form of
glycogen or lipids.