This book, prepared by participants of the European network COST ACTION 810 (1989-93) is the outcome of a meeting held in Switzerland (Einsiedeln, September 29 to October 2, 1993) on the "Impact of arbuscular mycorrhizas on sustainable agriculture and natural ecosystems". COST(Cooperation Scientifique et Technique) Networks were created in 1971 by the Commission of European Communities, and later enlarged to include non-European Member States, to promote pre-competitive scientific and technical research in fields of common interest. During the eighties, COST ACTIONS were launched in bio technological fields, including the network on arbuscular mycorrhizas. Arbuscular mycorrhizas are a universally found symbiosis between plants and certain soil fungi and essential components of soil-plant systems. They act as a major inter face by influencing or regulating resource allocation between abiotic and biotic components of the soil-plant system. Arbuscular mycorrhizas are involved in many key ecosystem processes including nutrient cycling and conservation of soil struc ture, and have been shown to improve plant health through increased protection against abiotic and biotic stresses. Sustainability can be defined as the successful management of resources to satisfy changing human needs while maintaining or enhancing the quality of the environ ment and conserving resources. Increasing environmental degradation and instability, due to anthropogenic activities and in particular the increasing fragility of the soil resource, has led to an increased awareness of the need to develop practices resulting in more sustainable natural and agroecosystems.

Inhalt
Taxonomy and phylogeny of the Glomales.- Biodiversity and characterization of arbuscular mycorrhizal fungi at the molecular level.- Characterization of arbuscular mycorrhizal fungi by immunochemical methods.- European Bank of Glomales An essential tool for efficient international and interdisciplinary collaboration.- Physiological characteristics of the host plant promoting an undisturbed functioning of the mycorrhizal symbiosis.- Recognition and infection process, basis for host specificity of arbuscular mycorrhizal fungi.- Ultrastructural analysis reveals the complex interactions between root cells and arbuscular mycorrhizal fungi.- Impact of mycorrhizal colonisation on root architecture, root longevity and the formation of growth regulators.- Biogeochemical cycling and arbuscular mycorrhizas in the sustainability of plant-soil systems.- Arbuscular mycorrhizas and agrosystem stability.- Hyphal phosphorus transport, a keystone to mycorrhizal enhancement of plant growth.- Approaches to the study of the extraradical mycelium of arbuscular mycorrhizal fungi.- Water relations and alleviation of drought stress in mycorrhizal plants.- Impact of arbuscular mycorrhizal fungi on plant uptake of heavy metals and radionuclides from soil.- Biocontrol of plant pathogens using arbuscular mycorrhizal fungi.- Management of positive interactions of arbuscular mycorrhizal fungi with essential groups of soil microorganisms.- Micropropagated plants, an opportunity to positively manage mycorrhizal activities.