Vesicular Arbuscular Mycorrhizae

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Vesicular Arbuscular Mycorrhizae

• Mohammad Reza Amerian
• April 2000

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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.

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Type of mycorrhizae and Taxonomy

• GLOMALES (ORDER)
• GIGASPORINAE
• Gigasporaceae
• Gigaspora
• Scutellospora
• GLOMINEAE
• Glomaceae
• Glomus
• Sclerocystis
• Acaulosporaceae
• Acaulospora
• Entrophospora

• Vesicular Arbuscular
  mycorrhizae (VAM or AM)
• Ectomycorrhizae (ECM)
• Ect-endo mycorrhizae
• Orchid mycorrhizae
• Ericoid mycorrhizae

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Arbuscules

• 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.

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Vesicles

• Accumulate storage product
• Intercellular
• Intracellular
• Function as propagules

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External Hyphae

• 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

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Global perspective on mycorrhizae
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Benefits Ascribed to Mycorrhiza

• Improved nutrient uptake
• Increase tolerance of
• Drought
• Salts
• Heavy metals
• Pathogens
• Enhanced soil stabilisation