Vesicular Arbuscular Mycorrhizae

Mohammad Reza AmerianMohammad Reza AmerianApril 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 Type of mycorrhizae and Taxonomyand Taxonomy

GLOMALES (ORDER)

GIGASPORINAE

Gigasporaceae

Gigaspora

Scutellospora

GLOMINEAE

Glomaceae

Glomus

Sclerocystis

Acaulosporaceae

Acaulospora

Entrophospora

Vesicular Arbuscular mycorrhizae (VAM or AM)Ectomycorrhizae (ECM)Ect-endo mycorrhizaeOrchid mycorrhizaeEricoid mycorrhizae

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.

Vesicles

Accumulate storage product

Intercellular Intracellular Function as

propagules

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

Global perspective on mycorrhizae

Benefits Ascribed to Mycorrhiza

Improved nutrient uptake Increase tolerance of

Drought

Salts

Heavy metals

Pathogens Enhanced soil stabilisation