EFFET DE L’INOCULATION ECTOMYCORHIZIENNE EN PÉPINIÈRE SUR LA CROISSANCE ET LA NUTRITION DES PLANTS DU CÈDRE DE L’ATLAS EN ALGÉRIE

Mycorrhizal inoculation of Atlas cedar seedlings in tree nurseries is one of the recommended technics for improving the survival and growth of trees in refo- restation sites. However, most trials have not succeeded in obtaining high rates of mycorrhization in seedlings inoculated with spores. The aim of this study was to determine the influence of sporal inocu- lum from three species of ectomycorrhi- zal fungi, Cortinarius cedretorum , Ama- nita vaginata and Inocybe  geophylla , on the growth and mineral nutrition of Cedrus atlantica seedlings. The carpo- phores, seeds and organic forest soils used to produce the seedlings were taken from beneath a pure stand of Atlas cedar. The sporal inoculum was made up of cru- shed and sieved carpophores. The diffe- rent growth parameters were assessed after 12 months of culturing: seedling height, length of the main root, number of fine roots, mycorrhization rate, total biomass, number of mycorrhized root tips and concentrations of mineral elements in the leaves. Mycorrhization rates for the three fungi species assessed ranged from 55% to 65%, which is exceptionally high for Atlas cedars inoculated with spores. The results show that inoculation with these three ectomycorrhizal fungi signi- ficantly increases leaf concentrations of phosphorus and nitrogen. Total biomass of the Atlas cedar seedlings was signifi- cantly higher with these three inocula than in the control seedlings.