1. WELCOME TO FUNGI
Fungal Nutrition & Classification
By
N. Sannigrahi, Associate Professor,
Deptt. Of Botany,
Nistarini College, Purulia (W.B) India
2. Nutrition of fungi is the process of procuring nourishment or
nutrient and is the principal function of the vegetative
phase(mycelium).The fungi, like all other organisms , require
in fairly large amounts for their mineral nutrition and other
constituents for growth. To basic nutritional needs of fungi
are-
i. A suitable organic compounds as source of carbon and
energy,
ii. A suitable source of nitrogen,
iii. Inorganic ions of sulphur, phosphorous, potassium and
magnesium in significance amounts,
iv. Inorganic ions of iron, zinc, copper, manganese and
molybdenum in trace amounts,
v. Certain amount of growth factors in trace amounts.
3. NUTRITION
Fungi are heterotrophic in nutrition as they can not
synthesize their own food. They can not get inorganic food
due to their simple structure. They can utilize organic and
inorganic compounds as their nutrients.
They are chlorophyll deficient plants and hence they
cannot manufacture carbohydrates using carbon dioxide,
water and sunlight
Fungi are with simple structural organization, thus they
always depends on dead or living organic matter for their
energy requirements. They are chemoautotroph.
On the basis of mode of nutrition, fungi are classified into
four groups:
Saprophytes- depends on dead and decay matters
Parasites- grow on the tissues of living plants and animals
Symbionts- mutual cooperation between two groups
Predacious fungi- developed mechanisms to capture small animals
4. SAPROPHYTIC FUNGI
Saprophytic fungi obtain nutrition from dead organic matter called
saprophytes.,
These fungi lives on dead organic matter or excreta of both plant and
animal origin
Examples: Mucor, Rhizopus, Penicillium and Aspergillus
Vegetative hyphae of these fungi directly absorb food materials from
organic matter
Saprophytic fungi may be of two types:-
Ectophytic saprophytes: grown on the surface of organic matter
Endophytic saprophytes: grown inside the organic matter
In some ectophytic fungi such as Rhizopus, special absorptive structures
such as rhizoids are developed for the easy absorption of food materials
Saprophytic fungi produce exoenzymes (enzymes which acts outside the
cell)
These enzymes digest the complex organic matter in the substratum into
simpler compounds to facilitate easy absorption by the hyphae
6. PARASITIC FUNGI
Parasitic fungi take food from other living plants or animals
called parasites
The living organism on which the fungi parasitize are called
host
Parasitic fungi are harmful to the host and they produce
disease condition in host organisms
The relationship of host and parasite in pathology is known
as parasitism
Parasitic fungi are of three types:-
Obligate parasites: these fungi can live only as parasite
on a living host Obligate parasites cannot live on dead
organic matter Example: Puccinia which cause rust disease
in several crop plants including wheat
Facultative saprophytes: They are parasites, but they
can also survive on dead organic matter in the absence of
living host Example: Taphrina
Facultative parasites: these fungi usually follow
saprophytic mode of nutrition Under certain conditions,
7. PARASITIC FUNGI
On the basis of location of parasite in host organism, the
parasites may be:
Endoparasite: parasite live inside the host tissue
Ectoparasite: parasite fungi which live on the outside surface
of host
Parasitic fungi possess specialized absorptive structures-
branched or unbranched called haustoria for the absorption of
nutrients from the host cells
Haustoria are specialized hyphal modifications either rounded
or button like structure
Haustoria may be intercellular (occupy between two cells) in
intracellular (occupy within the cell)
Size and shape of haustoria varies in different fungal groups.
The mycelia spread between the cells are called intercellular
mycelia and those enter the host tissues called intracellular.
9. SYMBIOTIC NUTRITION
These fungi grow on or with other living organism but both of them
are mutually benefited called symbionts
Lichens(algae-fungi) and mycorrhiza( root fungus) are examples
Lichens are the symbiotic association between algae and fungi
Here both fungi and algae are mutually benefited
Algae synthesize carbohydrates where as the fungi provides shelter
for algae
Mycorrhizae are the symbiotic association between fungi and roots
of some higher plants
Mycorrhizae helps in the absorption of nutrients by the host plant
Mycorrhiza may be ectophytic or endophytic
Ectophytic mycorrhiza are external mycorrhiza and they are
confined to the outer region of the roots
Endophytic mycorrhiza are internal mycorrhiza and they are found
deeply in the root cells
VAM or vesicular-arbuscular mycorrhizae are endotrophic because
of large vesicles and arbuscules within plant cell.
11. PREDACIOUS FUNGI
They are animal capturing fungi (predators) called predacious
fungi.
These types of fungi possess special hyphal traps called snares
to tap and capture small animals such as nematodes and
protozoa
They usually inhabit in the soil
They possess rapidly constricting hyphal traps which hold the
captive for long time
They also have haustoria which directly inserted into the tissue
of the prey
Some predacious fungi also produce sticky secretions for
capturing nematodes
Examples of predator fungi: Arthrobotrys, Dactylella,
Dactylaria
13. THANKS FOR YOUR JOURNEY
ACKNOWLEDGEMENT:
Google for images and information
A text book of Botany- Hait, Bhattacharya, Ghosh
Botany for degree students(Fungi)-Vasistha & Sinha
Mycology & Phytopathology-Mishra & Dash
This PPT has been developed for the academic interest of the undergraduate students of India & abroad without any business interest.