Transcript Document 7497869

Vesicular Arbuscular Mycorrhizae
Mohammad Reza Amerian
April 2000
Introduction
Mycorrhizae are mutualistic
associations or symbiosis between soil
fungi and plant roots that colonise the
cortical tissue of roots .
The host plant receives mineral
nutrients and water while the fungus
obtains photosynthetically derived
carbon compounds.
Type of mycorrhizae
and Taxonomy
GLOMALES (ORDER)
Vesicular Arbuscular
GIGASPORINAE
Gigasporaceae
mycorrhizae (VAM or AM)
Gigaspora
Ectomycorrhizae (ECM)
Scutellospora
Ect-endo mycorrhizae
GLOMINEAE
Glomaceae
Orchid mycorrhizae
Glomus
Ericoid mycorrhizae
Sclerocystis
Acaulosporaceae
Acaulospora
Entrophospora
Arbuscules
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Arbuscules are formed by
repeated dichotomous
branching and reductions
in hyphal width.
Arbuscules start to form
approximately 2 days after
root penetration.
Arbuscules are considered
the major site of exchange
between the fungus and
host.
Vesicles
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Accumulate storage
product
Intercellular
Intracellular
Function as
propagules
External Hyphae
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Type thick "runner"
or they are different
"distributive"
hyphae as well as
thin "absorptive"
hyphae
Responsible for
nutrient acquisition
Propagation of the
association
Spore formation
Global perspective
on mycorrhizae
Benefits Ascribed to
Mycorrhiza
Improved nutrient uptake
Increase tolerance of
Drought
Salts
Heavy metals
Pathogens
Enhanced soil stabilisation