The document describes the structure and reproduction of the fungus Agaricus, detailing its taxonomic position, mycelium types, and the basidiocarp formation. Key points include different stages of mycelium (primary, secondary, tertiary) and the development process of the basidiocarp, which consists of the pileus, stipe, and lamellae. Additionally, it explains the sexual reproduction process and highlights the formation of fairy rings associated with Agaricus campestris.

1. STRUCTURE AND
REPRODUCTION IN AGARICUS
Presented by: Ali Abbas Aslam
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2. Taxonomic Position
• Kingdom : Fungi
• Division : Basidiomycota
• Class : Agaricomycetes
• Order : Agaricales
• Family : Agaricaceae
• Genus : Agaricus
• Specie : A.campestris / A.californicus

3. Structure
Plant Body consists of two major parts:
1. Vegetative mycelium
2. Basidiocarp
Mycelium Basidiocarp

4. Vegetative
MyceliumIt may be:
Primary Mycelium
• Monokaryotic, short lived, develops from germination of basidiospore.
• Hyphae are septate and hyaline.
• Cells are short, contain oil globules, vacuoles and thin protoplasm.
Secondary Mycelium
• Dikaryotic, arise by dikaryotization through somatogamy of two
monokaryotic hyphae.
• Long, branched, septate and have short cells.
• Dolipore septa are present between adjacent cells.
• More abundant and produce mushrooms year after year

5. Vegetative Mycelium
Tertiary Mycelium
• Mycelium producing basidiocarps is sometimes referred to as tertiary mycelium.
• It forms complex tissue which produces basidia.

6. Reproduction
• Fungus reproduces sexually usually
• Definite sex organs are absent
• Plasmogamy is done by fusion of two compatible hyphae, which results in the formation of
a dikaryon
• The nuclei of dikaryon undergo conjugate divisions with that of the dikaryon to produce
dikaryotic secondary mycelium
• The basidiocarp develop from the hyphae of subterranean, perennial secondary mycelium

7. Basidiocarp / Sporophore
• The aerial part of the fungus is known as fruiting
body or basidiocarp. It is also called mushroom.
• It produces by tertiary mycelium

8. Structure of Basidiocarp
Pileus
• Upper part, circular and expanded, at young condition enclosed by
velum
Stipe
• Fleshy pinkish-white stalk, as pileus grow in size velum ruptures and
the remnants surround the stipe called annulus
Lamellae or Gills
• A cavity is present under the pileus in which large number of thin,
vertical, platelike structures are present called lamellae or gills
• Gills are first pinkish but as spore matures they become dark brown
Pileus
enclosed in
velum

9. Development of Basidiocarp
• It starts as a tiny swelling consisting of a knot of subterranean hyphae of the secondary
dikaryotic mycelium
• This swelling enlarges into a broadly ovoid structure the “basidiocarp primordium”
• Then a ring shaped cavity is formed “prelamellar chamber”
• The portion of the primordium above the prelamellar cavity finally develops into the pileus
and the below portion into the stipe
Development of Basidiocarp

10. Internal Structure of Basidiocarp
• Basidiocarp is composed of interwoven hyphae which run parallel to
each other in stipe
• They are compactly arranged to form pseudoparenchymatous tissue in
the pileus region
 In stipe the central hyphae is loosely arranged with prominent air
spaces forming the medulla
 The outer hyphae forms cortex
• The pileus also shows similar arrangement of hyphae into the central
medulla and outer cortex
• Some of the hyphae present in pileus develop into the lamellae or gills
Pseudoparenchymatous tissues

11. Structure of lamellae
• Each lamella consists of three parts:
Hymenium
Sub hymenium
Trama
Hymenium
• Fertile region, club shaped, binucleate forming palisade like layer on both sides of lamella,
they developed to form basidia
• Some are sterile and are called paraphysis
• Rest of them are elongated cells. They protrude beyond the paraphysis and are called
cystidia
Lamella

12. Trama
• Internal to hymenium is trama
• Multinucleated, elongated cells, extend from
hyphae of the pileus
• The hyphae run more or less longitudinally
Sub hymenium
• In between the hymenium and trama there
is region composed of hyphae arranged at
right angle to those of trama
• The cells are isodiametric and binucleate

13. • Karyogamy
• Formation of sterigmata
• Formation of basidiospore
• Hilum
• Separation from Basidium
• Context from Book
ofTanveer Ahmed Malik
Development of Basidium and Basidiospores

14. • The mycelium of Agaricus has a tendency to grow in all directions from a central point to
form a large invisible circular colony
• When the mycelium becomes mature at tips, sporophores are produced. These sporophores
appear in a circle.These circles of mushrooms are commonly called “fairy rings”
• A.campestris produces dark green rings in grass
• Damages the lawns, produce a thick fungal mat that prevents water from reaching the grass
roots below.
• Also deplete soil nutrients
Fairy Rings

15. Diagrammatic life cycle Graphical life cycle