fungi

1. NUTRITION IN FUNGI

2. CONTENT
 Nutritional requirements
 Essential Elements
 Source of Macroelements
 Modes of nutrition
 Mechanism of nutrition

3. INTRODUCTION
 The process of procuring nourishment or
nutrient and is the principal function of
the vegetative phase.
 The supply of nutrients is essential for
every living organism because the
nutrients serve as structural units and
also as energy source for the building up
of protoplasm which is the basis of life.

4. ESSENTIAL ELEMENTS
 The constituent of the organic and inorganic
substance which fungi make use of are C, O, H, N, P,
Mg, S, P, MN, Cu, Mo, Fe and Zn. Calcium is required
by some fungi but not all.
 The former are called the trace or micro elements and
the latter macro elements.
 The fungal growth is adversely affected or the fungal
fails to grow if one of the essential elements is
lacking in the culture medium.
 The macro elements are body builders and provide
energy for metabolic processes.

5. SOURCE OF MACROELEMENTS
 The organic substance usually utilized by fungi
are varied in nature.
 The carbohydrates are needed for building up the
body and also as a source of energy. in a typical
fungus, 50% of the dry weight is carbon of the
carbohydrates source of carbon, most fungi use
simple sugars.
 Glucose, for instance, is suitable for almost all
fungi. some fungi are able to make good growth
on fats as the only source of carbon.

6.  Basidiomycetes include most of the lignin
utilizing fungi. proteins, lipids, some organic
acids and higher alcohol are utilized by some
fungi as a sole energy source.
 Besides carbon, fungi require nitrogen. To
obtain nitrogen, they utilize both organic and
inorganic materials as the source. The chief
organic sources of nitrogen are protein,
peptide or an amino acid.

7. Hydrogen and oxygen are supplied in the
form of water which is the major constituent of
fungus mycelium forming about 85- 90% of the
entire weight.
 The chief among the inorganic nutrients which the
fungi require in fairly large amounts for their
mineral nutrition are sulphur, phosphorus,
potassium and magnesium.
 The form in which the major and the minor metallic
elements requirements are utilized is the anion.

8. The growth factor are catalytic in their
actions. To sum up the basic nutritional
needs of fungi are:-
1. A suitable organic compounds as a
source of carbon and energy.
2. A suitable source of nitrogen.
3. Inorganic ions of sulphur, phosphorus,
potassium and magnesium in
significant amounts.

9. 4. Inorganic ions of iron, zinc, copper,
magnesium and molybdenum only in
minute trace.
5. Certain vitamins or organic growth
factors in trace amounts.
 Besides the nutritional requirements
listed above the growth of fungi is
influenced by certain habitat factors
such as temperature, oxygen supply,
moisture, pH, value and by- products of
metabolism.

10. MODES OF NUTRITION
 The fungi lack chlorophyll. They are, therefore unable to
synthesize carbohydrate food from inorganic materials
and get it readymade from source external to
themselves.
 These heteronomous according their method of
obtaining food are divided into two categories, namely,
the saprophytic or saprobes and parasites. The
saprophytes cannot ingest solid food.
 The parasite lives in or on the living body of a plant or
plant or animal and absorbs organic molecules as
nutrients through the cell walls from the tissues of the
host.

11. MECHANISMOF
NUTRITION

12.  The whole mycelium may have the power to
absorb these nutrients or this task may be
assigned to special portions of the mycelium.
 The fungal hyphae secret enzymes which convert
insoluble complex food materials in the
substratum to soluble once.
 The hyphae either ramify in the intercellular space
between the host cells or penetrate into the host
cells.
 The intercellular hyphae obtain nutrition through
the cell walls or membrane of the host cells.

13.  The intercellular hyphae of
some highly specialized plant
parasites give out slender,
lateral outgrowths. It
punctures the host cell wall
making a minute pore through
which enters the host cell.
 This type of feeding organ of
the parasitic fungi is called a
haustorium.
 The haustorium is intracellular
and thus robs the host of its
food without killing it.
Haustorium are characteristic
of obligate parasites.

14.  The fungi as mentioned above are unable to
synthesize sugars from carbon dioxide and water.
 Many fungi obtain nutrition by living in mutually
beneficial associations with other plants.
 The association is not causal but permanent and is
established during long process of evolution.
 The two best known examples of mutualist
associations of fungi with other plans are
Symbiosis and Mycorrhiza.

15. a. SYMBIOSIS
• The common example of
Symbiosis is an association of
a fungus and an Alfa in a lichen
thallus.
• The duty of alga in this
partnership is to synthesize
food with the help of green
chloroplast and share it with
its fungal partner.
• The fungal absorbs minerals in
solution and water from the
substratum and passes them
on to alga.

16. b. MYCORRHIZA
It is defined as the symbiotic
associations between the hyphae of
certain fungi and roots of plants. It
is of three types:
1. Ectomycorrhizal
2. Endomycorrhiza
3. Ectoendomycorrhiza

17. • The fungal hyphae in this
case form a complete
envelope around the root
tip and also penetrate and
extend into the first few
cortical layers to form an
intercellular network of
hyphae known as the
Hartignet.
• The presence of the
fungus thus increases
root absorption.
I. Ectomycorrhiza

18. • The fungal hyphae in this
case penetrate root
hairs.
• Epidermis and reach the
cortex where they grow
intracellularly forming
fungal knots in the
cortical cells.
• A portion of the
mycelium lives in the soil
but it forms no dense
hyphal growth.
II. Endomycorrhiza

19. • It is a combination of
the first two.
• The fungal hyphae
form a sheath at the
surface of the root.
• Within the root they
grow intercellular and
intracellular.
III. Ectoendomycorrhiza

20. REFERENCES
Botany For Degree Students Fungi
by : B.R.Vashishta & A.K. Sinha
https:// WWW.