CHAPTER 19
REPRODUCTION OF PLANTS THROUGH SPORES
Systematic position of Mushroom
Kingdom: Plant
Sub-kingdom: Cryptogams
Division: Thallophyta
Sub-division: Fungi
Type: Mushroom
Mushroom is non-vascular, multicellular, saprophytic fungus growing in
dark, moist and shady places on decayed organic matter.
Body of mushroom consists of two parts viz: mycelium (hypha) and the
fruiting body or basidiocarp.
Mycelium is a thin thread like vegetative part of a mushroom that lies
underground.
Fruiting body or basidiocarp is an above-ground fruiting body of a
mushroom that bears basidia and basidiospores. It is umbrella shaped
and is composed of pileus, gills and stipe.
Gills of mushroom
basidiospores.
bears
thousands
of
basidia
that
produce
Mushroom reproduce asexually by means of basidiospores. The
basiodiospores germinate and form monokaryotic primary hyphae.
Two primary hyphae of opposite strains fuse to form dikaryotic
secondary hyphae.
After maturation, under favourable condition the secondary mycelium
develops a fruiting body called basidiocarp.
Edible mushroom
Agaricus campestris (Seto chyau)
Agaricus bisporus (Gobre chyau)
Poisonous mushroom
Amanita verna
Amanita phalloides
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Fig. Life cycle of mushroom
Systematic position of Fern
Kingdom: Plant
Sub-kingdom: Cryptogams
Division: Pteridophyta
Type: Fern
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Ferns are the most developed non-flowering plants. They are also
known as vascular cryptogams as they have well developed conducting
system.
The plant body of a fern is sporophyte and is differentiated into root,
stem and leaves.
Fern has underground modified stem known as rhizome. Rhizome is
covered with brown scaly hairs called ramenta.
Leaves of fern plant is pinnately compound and is known as fronds or
pinnae.
Under surface of leaves of fern plant bears numerous black or brown
kidney shaped structure known as sori.
Sori is the collection of numerous spore-bearing spore sacs called
sporangium.
Indusium is the kidney-shaped protective covering of sori that envelops
the sporangia.
Prothallus is the first gametophytic stage of fern plant. It is green, dorsoventrally flattened, heart shaped structure that bears antheridia and
archegonia.
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Fig. Life cycle of fern plant
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Important Questions
1) What is secondary mycelium in the life cycle of a mushroom?
Secondary mycelium is a dikaryotic mycelium formed after the fusion
of two primary mycelium of opposite strains.
2) Write any two differences between primary mycelium and
secondary mycelium.
Primary mycelium
Secondary mycelium
Primary mycelium is formed by Secondary mycelium is formed
the
germination
of by the fusion of two primary
basidiospores
mycelium
Primary
mycelium
is Secondary
mycelium
is
monokaryotic
dikaryotic
3) “Both asexual and sexual reproduction is necessary to complete
life cycle of fern.” Justify this statement.
Fern plant reproduces both asexually and sexually. It reproduces
asexually by means of spores. Spores germinate to form a
gametophytic tissue prothallus. Prothallus bears antheridium and
archegonium which produces antherozoids and ovum respectively.
Sexual reproduction is achieved by the fusion of antherozoids and
ovum to form an oospore. Thus there is regular alternation of asexual
and sexual reproduction in the life cycle of fern plant.
Nawal Shrestha/Rosebud School
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