MUSHROOMS
These are aerial expressions of vegetative(hyphal)growth of fungi in the substrate. The substrate may be
decaying log of wood, tree bark or other dead organic matter Although its macroscopic expressions are
now used for all human activities, including nutrition and medicine, it was not originally designed for
these purposes. It is designed to bring to the open the spores in order to allow multiplication. The actual
organism lives organically under the ground or inside wood, reveals presence only by fruiting. The aerial
growth is a reaction to environmental stress, most times, nutrient stress
Fig .1 A typical mushroom
Benefits /significance
A. As food for man e g Agaricus spp, Pleurotus spp
1.Rich in protein, vitamin (B, B2, & C) and has many minerals. The nutritional content is
located within the chitinous cell wall. Has no sodium, and cholesterol
Water content- 90%
2. Protein- 3-4% (retained by N2 content x 6.25)
Dry weight- 20-35%
3.Contains all essential amino acids. Lysine, inadequate in cereals, is in abundance in
mushrooms
4.Fat- unsaturated fatty acids (healthy to man) are in abundance is Linoleic acid
5.Vitamins and rich in minerals- Thiamine (B1), Riboflavin (B2), Ascorbic acid (C), Niacin &
Biotin, P, K. Na
6 Fresh mushroom contains fibres and carbohydrates
B. As medicine
1.lowers cholesterol level, reduces heart and coronary disease
2.suppresses the growth of tumours
3 controls effect of diabetes eg Plenrotus, Lentinula
4.reduces infections through the production of antioxidants eg Ganodema, Auricalaria,
C. In environmental remediation
1. neutralizing of polluted or acidic soil
, 2.degrade lignin, hemicelluloses like the basidiomycete white rot (lignin degrading) fungi.
The white rot fungi can degrade lignin & hemicelluloses leading to the wood turning white, a
process called bio-bleaching
3.break down poly aromatic hydrocarbons (PAH)e.g. Phanerochaetes chrysosporium and
Coriolus versicolor- both produce extra cellular enzymes
D.Ancient people linked mushroom to the gods,
E.No arable land is needed for their cultivation
F.Agricultural waste can be turned to fertilizer
.
Structure
A typical mushroom is a thallus with a head called pileus under which the gills are attached. The stalk or
stipe is the structure o which the pileus rests. It has a typical septum called Dolipore septum, known to be
barrel shaped, Fig 9.2. Usually there are absorptive structure at the base to assist in carrying out enzyme
action on the substrate.
Fig .2. Dolipore(barrel shaped )septum
This structure, called the fruit body is designed to expose and release spores for reproduction, particularly
in their natural state, in the wild. Basidiospores are a product of meiosis(Fig 9.3)
Mushroom poisoning = mycetism e.g Amanita phalloides
The Chinese pioneered mushroom cultivation in the year 1313.
Wood ear mushroom- Auricularia sp and White bottom mushroom- Agaricus bisporus are
examples
“Spawn”=mushroom seed=pre-grown mycelium, free of contaminants, mixed with sterile substrate
Fig 3 Basidiospore formation from meiosis
In practice, spores are not used to cultivate mushrooms because ;
it is difficult to germinate early enough to prevent bacteria
the genetic component of spore can be different from the mushroom
it has small size, difficult to handle
Growth and Life Cycle
A mushroom has millions of spores each of which can germinate & branch to form a mycelium. Two
types of thallism are exhibited
Homothalism=resources for sexual reproduction are present in a single organism/mycelium eg Volvariella
volvacea
These are aerial expressions of vegetative(hyphal)growth of fungi in the substrate. The substrate may be
decaying log of wood, tree bark or other dead organic matter Although its macroscopic expressions are
now used for all human activities, including nutrition and medicine, it was not originally designed for
these purposes. It is designed to bring to the open the spores in order to allow multiplication. The actual
organism lives organically under the ground or inside wood, reveals presence only by fruiting. The aerial
growth is a reaction to environmental stress, most times, nutrient stress
Fig .1 A typical mushroom
Benefits /significance
A. As food for man e g Agaricus spp, Pleurotus spp
1.Rich in protein, vitamin (B, B2, & C) and has many minerals. The nutritional content is
located within the chitinous cell wall. Has no sodium, and cholesterol
Water content- 90%
2. Protein- 3-4% (retained by N2 content x 6.25)
Dry weight- 20-35%
3.Contains all essential amino acids. Lysine, inadequate in cereals, is in abundance in
mushrooms
4.Fat- unsaturated fatty acids (healthy to man) are in abundance is Linoleic acid
5.Vitamins and rich in minerals- Thiamine (B1), Riboflavin (B2), Ascorbic acid (C), Niacin &
Biotin, P, K. Na
6 Fresh mushroom contains fibres and carbohydrates
B. As medicine
1.lowers cholesterol level, reduces heart and coronary disease
2.suppresses the growth of tumours
3 controls effect of diabetes eg Plenrotus, Lentinula
4.reduces infections through the production of antioxidants eg Ganodema, Auricalaria,
C. In environmental remediation
1. neutralizing of polluted or acidic soil
, 2.degrade lignin, hemicelluloses like the basidiomycete white rot (lignin degrading) fungi.
The white rot fungi can degrade lignin & hemicelluloses leading to the wood turning white, a
process called bio-bleaching
3.break down poly aromatic hydrocarbons (PAH)e.g. Phanerochaetes chrysosporium and
Coriolus versicolor- both produce extra cellular enzymes
D.Ancient people linked mushroom to the gods,
E.No arable land is needed for their cultivation
F.Agricultural waste can be turned to fertilizer
.
Structure
A typical mushroom is a thallus with a head called pileus under which the gills are attached. The stalk or
stipe is the structure o which the pileus rests. It has a typical septum called Dolipore septum, known to be
barrel shaped, Fig 9.2. Usually there are absorptive structure at the base to assist in carrying out enzyme
action on the substrate.
Fig .2. Dolipore(barrel shaped )septum
This structure, called the fruit body is designed to expose and release spores for reproduction, particularly
in their natural state, in the wild. Basidiospores are a product of meiosis(Fig 9.3)
Mushroom poisoning = mycetism e.g Amanita phalloides
The Chinese pioneered mushroom cultivation in the year 1313.
Wood ear mushroom- Auricularia sp and White bottom mushroom- Agaricus bisporus are
examples
“Spawn”=mushroom seed=pre-grown mycelium, free of contaminants, mixed with sterile substrate
Fig 3 Basidiospore formation from meiosis
In practice, spores are not used to cultivate mushrooms because ;
it is difficult to germinate early enough to prevent bacteria
the genetic component of spore can be different from the mushroom
it has small size, difficult to handle
Growth and Life Cycle
A mushroom has millions of spores each of which can germinate & branch to form a mycelium. Two
types of thallism are exhibited
Homothalism=resources for sexual reproduction are present in a single organism/mycelium eg Volvariella
volvacea
