Article

Generai aspects of the structure of forest tree mycorrhizae and of the physiological and ecological consequences of the establishment of symbiosis are reviewed. A long-terrn research programme on the use of controlled mycorrhizal infection to improve the quality of the forest seedlings and mediterranean reafforestation is described, and preliminary results are presented: obtention of mycorrhizal isolates suitable for mediterranean forest species; screening of these isolates using physiological criteria; production of mycorrhizal seedlings and characterization of the mycorrhizae; measurement of the physiological effects of mycorrhizal infection in the nursery; definition of the ecological ability of selected isolates; set-up and follow-up of the ecology and ecophysiology of the experimental wood lots.